"if it relies on 32 bit libraries"

the last 32bit only Mac system shipped a decade prior to Catalina. 32bit was dropped a decade after support for the last 32bit only Macs. Apple Silicon in both iOS and Mac is 64bit only, on iOS it has been for years.

Despite that, macOS supports everything required for proton - the mechanisms that allow wine to run 32bit x86 apps on both intel and under rosetta exist pretty much purely for the purpose of things like wine (and so proton).

So I'm not sure where you get "apple cut off the proton devs" from that work