I liked playing osu! on Linux through Wine since it offered much lower audio and input latency than you could achieve on Windows. Minecraft has also always been a safe bet on Linux (unless you enabled shaders, then it just turned into a visual abomination for just about every shaderpack).
Generally OpenGL games weren't too bad, DirectX however... the biggest change here was DXVK rather than Proton.
Never thought we'd get to where we are now.
For Monado on Windows iirc the current state is that it works but not with real hardware (which is usually well supported officially anyway) due to lack of drivers. Now if it becomes the only platform to keep supporting WMR the developer incentive is definitely there.