Digitizer issues are usually from getting the wrong digitizer. They are programmed differently for the HAC-001(-01) (v2 classic switch) vs the HAC-001 (v1 classic switch).
More specifically the game card reader board that the digitizer plugs into needs to match. So make sure you buy your digitizer to match the game card reader version, or buy a game card reader to go with it (you can get them for ~$14). Unfortunately many digitizer sellers on eBay don’t say which model it is designed for.
Alternatively you can mix and match those versions if you have an unpatched/modded switch. Just launch Hekate, go to tools and run the digitizer calibration.
I haven’t repaired too many switches but the first time it happened to me I had a spare v2 game card reader and that fixed it immediately. Second time I used the Hekate method and that worked just as well
The switches don’t have to control the lights they are wired to. I have Inovelli z-wave switches, and on these you can disable the relay. So the switch can still send out commands/scenes on the network but the relay is always on.
Then you would put in a relay unit in the electrical box of the lights or if you have enough room in with the switches. Then setup the switches to control their respective sets of lights.
Might even be a switch out there that lets you disconnect the relay from the buttons on the switch but still control the relay which would cut down on the device count.