If you had rosetta it would be able to self-update to the new universal binary, without it you have to do this one update manually.
$ file steam_osx
steam_osx: Mach-O universal binary with 2 architectures: [x86_64:Mach-O 64-bit executable x86_64] [arm64]
steam_osx (for architecture x86_64): Mach-O 64-bit executable x86_64
steam_osx (for architecture arm64): Mach-O 64-bit executable arm64
% file /Volumes/Steam/Steam.app/Contents/MacOS/steam_osx
/Volumes/Steam/Steam.app/Contents/MacOS/steam_osx: Mach-O universal binary with 1 architecture: [x86_64:Mach-O 64-bit executable x86_64]
/Volumes/Steam/Steam.app/Contents/MacOS/steam_osx (for architecture x86_64): Mach-O 64-bit executable x86_64% file steam_osx
steam_osx: Mach-O universal binary with 1 architecture: [x86_64:Mach-O 64-bit executable x86_64]
steam_osx (for architecture x86_64): Mach-O 64-bit executable x86_64
A custom driver could always be made by the community. It feels a little absurd to expect Valve to write and support four different gamepad drivers, when they only need one.
That is what the entire industry does though. Imagine if you needed an application running in the background for every peripheral you have, for your monitor, for your GPU, for running a hotspot on your smartphone over USB. Imagine having to install a piece of software to access a thumb drive. And that all those applications also needed user accounts. That is the entire point of having drivers.