Hello,
First question is did you check and re-check the wiring of the board? I did this exact upgrade (which is awesome btw, so good call in the first place) and I struggled to get some of the wires to talk nicely. I think I damaged a connector a bit removing the hot glue that comes on the stock board to hold connectors in place. I would check that first due to my previous experience.
Second question is what .bin file did you put on the SD card? I have a BLTouch and like to edit the firmware to my liking so I was playing with that anyway, but I have heard that the github files aren’t always the best.