First, firmware version? Send M115 or M122 and post reply.
M569 P5 R1 T2:2:10:10 S0 ; Extruder0 - BreakoutBoard_Driver5 - new Z Axis Left
M569 P6 R1 T2:2:10:10 S0 ; Extruder1 - BreakoutBoard_Driver6 - new Z Axis Right
These timings are still too fast. Is the problem that the Z doesn't move at all? Once you have the signal voltage correct (0 to 5V), increase the first two numbers. Try T2.5:2.5:10:10 and if that doesn't work T5:5:10:10.
M671 X-20:220 Y400:400 S0.5
You need this line to level the bed. Your M208 is M208 X800 Y800 Z760:760 S0, so I guess your leadscrews are at something like
M671 X-50:850 Y0:0 S0.5
But make sure the motor on the left (at X-50) is plugged into stepper driver 5, and the motor on the right is plugged into stepper driver 6 (defined by M584 ... Z5:6 ... ).
M92 X80.00 Y80.00
M92 Z800:800 ; set steps per mm
M566 X6000.00 Y6000.00 Z60.00:60.00 U60.00 E120.00:120.00 ; set maximum instantaneous speed changes (mm/min)
M203 X30000.00 Y30000.00 Z1000:1000 U1000 E1800.00:1800.00 ; set maximum speeds (mm/min)
M201 X5000.00 Y5000.00 Z250:00:250.00 U250.00 E250:250 ; set accelerations (mm/s^2)
A few errors here. E92 is not a valid gcode command. for M566, M203, and M201, each axis only takes ONE value, except E which takes a value for each E axis. Remove the U values. Try this instead:
M92 X80.00 Y80.00 Z800 E400:400 ; set steps per mm
M566 X6000.00 Y6000.00 Z60.00 E120.00:120.00 ; set maximum instantaneous speed changes (mm/min)
M203 X30000.00 Y30000.00 Z1000 E1800.00:1800.00 ; set maximum speeds (mm/min)
M201 X5000.00 Y5000.00 Z250.00 E250:250 ; set accelerations (mm/s^2)
M906 X2000 Y2000 I0 ; set motor currents (mA) and motor idle factor in per cent
M906 E800:800 I50
Be aware that setting M906 I0 will mean motors turn off after the idle timeout period, and will need to be rehomed or will lose position.
For the bed.g, change the probing points to the size of your bed. You shouldn't need the M401 and M402 commands:
M561 ; clear any bed transform
; G29 ; probe the bed and enable compensation (I would comment out this line, and do mesh compensation separately)
G28 ; home
G30 P0 X15 Y400 Z-99999 ; probe near a leadscrew, half way along Y axis
G30 P1 X785 Y400 Z-99999 S2 ; probe near a leadscrew and calibrate 2 motors
For now, BL Touch is disabled, as i am missing some resistors to getting the 3.3V Signal output.
What board version is you Duet 2 WiFi, and what version BLTouch? Because it's only early Duet 2 WiFi boards that can't cope with higher voltages on the Probe.In, and only early versions of BLTouch that don't work happily on 3.3V or 5V. It's unlikely you have early versions of both, so probably no need for resistors, or cutting the trace. See https://duet3d.dozuki.com/Wiki/Connecting_a_Z_probe#Section_For_all_Duet_2_WiFi_Ethernet_boards_prior_to_version_1_Num_04
I would try the BLTouch on 3.3V and see if it works.