There is no hold labeled ground that is connected to the depth pot. There is a hole labeled “GND” on one corner of the board, is that what you are talking about?
You’ll know the relay is working because you’ll hear it click when you press the bypass switch. If it is not working then that may be your problem (or at least one problem). You’ll need to double check your solder joints (especially look for bridges) where the wires solder to the board from the switch and on the switch itself. Also check the solder joints around the relay.
-Brach