I just finished a test print with 100% success. Thanks for the suggestions.
I think the major problem was that I never removed the gap from when I was printing both the model and support with pla. I had completely forgotten about this.
I also printed slower although I don't actually know which of the many speeds is used - I suspect it was 26 mm/sec for petg and pla at 40 mm/sec.
The petg and pla stuck together to a limited degree ... enough to hold everything together yet not so much as to make support removal difficult.

I only have two words ...... Woooooo Hoooooo !

If your offset values are zero, you are probing points that the Duet doesn't know about and you are then taking those probing points to adjust the mesh height. You are creating a bad height map and then applying it.
I don't understand how you can possibly expect any results but crap. You might as well work without any height map.
It's odd that you get stripes but before anyone can give you any suggestions about what is wrong, you MUST set things up properly !!!

Moderators .... could we please lock this thread and stop with the negativity please ?

<sigh>
Now we have three threads for the same issue.

I would like to add my 3 cents (good grief, It turned into a $30 'Mobby Dick' novel). It's been said before - the support from both Duet and the community is incredible. There have been many occasions where I was impressed about the amount of patience and knowledge that is shown every day.
Having said that, there are only so many things that can be done when one is sitting in front of a computer, totally removed from the actual device that is causing issues. Things that might be immediately obvious sitting in front of the Duet may take days and days to sort out remotely.
I have had my fair share of "operator problems", Some I have had sorted by people here, some I have fixed myself after bouncing the issue off people here and they got me thinking the right direction and then there were too many issues that just took hours or even days of screwing around before the light went on.
I have learned an incredible amount by pounding my head against the wall and sticking with a problem and reasoning things out. You probably don't want to hear that but immersion into the whole 3D printer scene is pretty mandatory if you are going the "self built" Duet route. It is not a product that is turnkey - it is a small part of a large and complex machine. A machine that Duet has no control over.
It is not fair to purchase a car engine and expect the manufacturer to be able to figure out why the car that you built around the engine tops out at 50 km/hr for some reason.
In addition to all that, the Duet 3 and RRF3 is a new product that is still being developed as I type this and changes to the software happen on a regular basis. It is not a 'stable' product as the Duet 2 series is. There is a steep learning curve to go from RRF2 to RRF3. I still work with a Duet2 but have migrated to RRF3 which was a big step for me. A step that isn't for everybody at this stage.

I can only suggest to stick with it and eventually it will 'click'. This applies to the Duet to some extent but I would say that it is less a Duet issue and more of an issue of the whole 3D scene.

I don't recall what your particular issues are. Maybe you are doing something that has never been done before, maybe you are doing something that is a real challenge even for a person that has been involved in 3D printers for many years. You can't expect things to just magically work. Thankfully, the community around the Duet shows incredible patience and sometime I must admit, more patience than I would ever be able to muster.

Sometimes it helps to approach a problem from a different perspective. Start a new thread along the new direction and maybe we can help you that way and eventually get to your current problem via a back pathway.

I find that sometimes it is necessary to take a break for a couple of days. More often than not, this will clear up my thinking and new avenues will open up.

Last but not least, you can't expect to purchase all the bits and pieces for a printer and expect to have a working unit in a given time frame. It requires time to develop a new product and when you build a new printer that is exactly what you are doing.
Sometimes, when you NEED a printer in a month, it might be best to buy a commercial product with full support and satisfy your desire to build a printer when you don't have the pressures of needing it in a month or 6 .....

It is highly unlikely that the SSR has failed since it is not stuck in the 'on' position. It is way more likely that there is a wiring error.
Are you aware that the positive line will always be high no matter if the heater is on or off?
Simply wiring the negative to ground will cause all these issues.
Verify the ruting of the two control lines.

@Co3get, here is my heater section of config.g:

; Heaters

M308 S0 P"bedtemp" Y"thermistor" T100000 B4200 ; configure sensor 0 as thermistor on pin bedtemp
M308 S3 P"e2temp" Y"thermistor" A"bed sense 2" T100000 B4200 ; configure alternate or second bed heat sensor
M950 H0 C"bedheat" T0 ; create bed heater output on bedheat and map it to sensor 0
M140 H0 ; set bed heater to heater zero
M143 H0 S120 ; set temperature limit for heater 0 to 120C
M307 H0 B0 S1.00 ; disable bang-bang mode for the nozzle heater and set PWM limit
M308 S1 P"e0temp" Y"thermistor" T100000 B4200 ; configure sensor 1 as thermistor on pin e0temp
M950 H1 C"e0heat" T1 ; create nozzle heater output on e0heat and map it to sensor 1
M143 H1 S280 ; set temperature limit for heater 1 to 280C
M307 H1 B0 S0.6 ; disable bang-bang mode for the nozzle heater and set PWM limit
M308 S2 P"e1temp" Y"thermistor" T100000 B4200 ; configure sensor 2 as thermistor on pin e0temp
M950 H2 C"e1heat" T2 ; create nozzle heater output on e0heat and map it to sensor 2
M143 H2 S280 ; set temperature limit for heater 2 to 280C
M307 H2 B0 S0.6 ; disable bang-bang mode for the nozzle heater and set PWM limit

It's been a while since I set that up so am not too sure what all was done.
I do know that in order to display the second bed temperature on the graph in DWC, you need to go into the 'Extra' bit of the 'tools and extra' pane and flip the 'show in graph' thingy.

Hope that helps.

Yes, middle of bed for the sensor, offset a bit to not be directly where the bed wires go into the heat pad. I don't think it makes much difference exactly where it is located as long as it is somewhere in the middle-ish.

And if you find that the 'pull test' is not passed then double up the BARE wire at the larger connector of the Duet. Solder on the wiring is bad juju!

Chances are that your home switch is defective.
Printer tries to go 'home', switch is already closed/open/whatever and the Duet says 'I am here and now I need to go to the zero position which is 10 mm from the switch'
This will repeat forever.
I would suggest pulling the wires for the home switch and see what happens. If you get the same result, short the x home switch terminals at the board and see what happens.
If the action doesn't change then either the config.g file is set up incorrectly or there is something wrong with the Duet.

If you have a multi meter, pull the x home plug and throw the meter onto the cable connections and see if pressing and releasing the home switch has the expected results.

Don't worry about the section it is in. My point was that there are fundamental issues and chasing 'minimum extrusions' is the wrong thing (IMHO) to do at this point. Once you get a basically good print but have minor issues, then you go and tweak for those little issues.
I can't really suggest anything based on the pictures I am seeing - there is blobbing, there is under extrusion and other stuff.
About the only thing I can suggest is to start at square one tuning absolutely everything. Don't bother with anything past the first layer until you have the first layer worked out.
One aspect of the first layer is that the traces do not meet - either you are under extruding or your gap between build plate and nozzle is too large.

Those prints look horrible ... this is not minor 'tweak' issue but a very fundamental error someplace.

@stuartofmt, just FYI, I gave up and went back to the BLTouch. Yes the BLTouch is less accurate but certainly accurate enough and it is a hell of a lot more consistent. You can use it no matter what the phase of the moon is!

I must admit that I am just way too invested into fusion360 (Autodesk's evil plan worked). I will see what happens Oct 1 when the changes take affect.

I am going to stir the pot here and say that two to one hot ends can also be used by different filament materials as long as they have similar heat ranges.
Having said that, I use a Chimera setup which, while being able to use two different materials, has a bunch of other issues.

Stirring a bit more, I would say that neither of these two solutions are as good as what the uninitiated would think.
I am thinking/hoping that a tool changing hot end might be the answer but that concept is still in it's infancy.

So, to sum it up, short of those things that have completely enclosed support where disolvable support is required, you will likely trade one frustration for another frustration.

To add a bit more - a lot of times the support can be removed easily when everything is printed in the same material if everything is tuned right and the right options are chosen in the slicer. It's a tricky balance but I have had prints where support is very easy to remove. For me it's a combination of knowledge and luck to hit just the right combination. I am sure there are many people out there that do not depend on luck to hit the magic point where everything just works.

Classical case of bad connection. could be the solder joint on the board or the terminal screw not being tight.

Truth be told, I also like designing things from scratch in a lot of cases but when you have a model that works and only needs a few fillets to strengthen corners then it's just easier to re-use the existing models. Other models might work but need additions - no point in re-designing from scratch.
Turns out that when I was trying to convert the mesh to a solid in Fusion360 I forgot one step - turning off history before the Tspline to brep step. It doesn't work when you have history on for whatever reason.

The 'slowness' I reported earlier was a simple step of selecting an edge and applying a filet - it took an amazing long time to do that one single operation.

I agree with you, I have to set time aside for re-learning things.

Thanks! It seems abundantly clear that I don't know enough about FreeCAD any more even though I have used it in the past.
I did manage to make a single filet on the model but that took an amazingly long time to do - long enough to make it unusable. I do not know if this is the result of the computing power available (Fusion360 runs on a seperate, dedicated windoze machine, it's the only windoze software I use) or is the fault of the software.
In any case, I will need to start from scratch with FreeCAD as I just don't know enough to test it at the moment.

I was able to transform another stl into a solid but do not know what I am doing yet so editing that new solid was a no go. Time to do some practice work by re-creating the object that I was not able to convert from the stl file.

Interesting .... I wonder why FreeCAD itself reports it as a solid.
I will try and import another stl and see how it does.

Thanks!