Maybe Valve can port proton to mac

That would not help. The reason proton works so well is because Linux on x86 and Windows on x86....are both on x86.

Proton on ARM Mac's would involve Rosetta and while that does a surprisingly good job of running x86 on ARM I'm not sure it's up to the job of running games at high speed...

Games seem playable running through Microsoft’s inferior x86 compatibility layer in a Windows ARM VM on M1 Pro/Max, so I don’t see how running games through Rosetta would be any worse.

If you have some monster like 3090, you expect it to run games smoothly on “ultra” settings. In reality, some games are pushing its limits even on “middle” settings (Cyberpunk 2077 @ 2k, RDR2 @ 4k). Any emulator will hit performance, so if you want some top-of-the-top performance - you still need Windows PC with RTX 3090. And it will not be even more expensive than Mac Studio ;)

I want my game to vsync with my monitor. That is all I care about.

Your 4k monitor?

I have a 5k monitor, but yes. That is literally all I care about.

Congratulations, no video card in the world is able to keep up a 5k res at 60FPS while doing even slightly demanding things. Nor will the M1 Ultra be.

My 3090 can drive 4k100hz for most demanding games at their highest settings.

Some games are a stable 4k120 and others are more like 4k75.

I feel the 3090 could feasibly drive 5k60 as a result.

They are not the most demanding games, that's why :)

Real world example M1 Max;

GTAV on Win11 Arm VM - okay, but not great.

GTAV on Crossover - much much better, lack of joystick support (but that's a crossover issue)

They used to have a Proton port for Mac, and discontinued it.