Some may have followed the z-probe issue I had, unfortunately it wasn't the z-probe after all, rather a coordinate system problem.
When i repeatedly probe the same spot 100 times I get a strong drift of the coordinate system. So much so I get a funny looking curve that shows a drift of apprx 200-300 mue for roughly the first 30 attempts and than levels out. You may think this is not important as I will not be probing the same point 100 times ever anyway, however when doing the mesh bed leveling, 30 points that are constantly off a couple of mue give you a very tilted bed. Let alone when you are using more than one tool.
So the first thing I did was to eliminate the "Idle" Setting, setting the I Value from 30 to 100. This resulted for me in a reduction of the drift of roughly 100 mue leaving me with a total drift of apprx. 150 mue. This is the whole test including the setup I used that you may verify. 150mue is still too much for my taste, as it should actually be 0 or at least oscillating around a value and not drifting into one direction.
I have the same issue with my duet3 on a similar system, with only a 150 mue drift. I also set up a klipper, using the same drivers, with the same result. Inly my Kossel Mini running on the Mega/Ramps/Marlin setup does not have this issue.
Please if anyone has an idea, please let me know what you think could be causing this drift!