They'll need that either way if they want to get back onto macOS, even if it's separate binaries and not a translation layer. At this point I think Steam basically doesn't work on Mac? Since the x64 Macs are legacy and the new ones are aarch64

It technically works since ARM macs can still run x86 binaries. But it's so slow and buggy, and the selection of playable games so slim that there is almost no point.

I doubt fex-emu works on macos.

But isnt that what Rosetta2 is for on mac anyway?