Sorry, I'm just imagining you in a heated battle and the wheelchair losing connection and immediately reverting back to controlling itself and thus flinging you around. ;-)
Have you looked at Steam Input? You can do a ton of stuff with it, maybe even combine multiple controllers. You can even use it with none-Steam games by adding the executable to Steam. It only has problems with flatpaks.
Or maybe look people working on Joycon support. I think they are technically two controllers that you would sometimes like to act as one.