I'm not an expert so I may be wrong,
In your config.g file, you created the BLtouch servo pin using
M950 S0 C"exp.heater3" ; create servo pin 0 for BLTouch
Note 'S0'
In your deploy and retract files, you are calling for servo pin7
M280 P7 S90 ; retract BLTouch
Note 'P7'
In the G-Code Wiki
"RRF3: Before you can use M280 you must create a GPIO port using M950. Then in the M280 command, the P parameter is the GPIO port number, not the logical pin number. Duet 2 supports up to 10 GPIO ports, numbers 0 to 9. No GPIO ports are allocated by default."
Try changing the P7 to P0 in both retractprobe.g and deployprobe.g files