Signal is analog but there is a sub board with an HX711 and a SPI chip.
You could wire a switch in place of the loadcell but that seems to be overly complicated.
As for sensor less homing the pin ID’s are connected with the diag pin on the motor driver. NOTE the motor sockets are labeled for the corresponding INPUTS to the motor driver. They are wired to the motor driver outputs and are actually [A+][A-][B+][B-] to the motors.
You may want to update the Amrbian distro running on the H616 SOM. It will run the newest Armbian build for the BTT CM1 with a couple small tweeks.