I’ve used that package as well for a while. And depending on ones needs it is perfectly usable even for gaming. In this regard noticing a difference to the closed variant is difficult. And they’ve recently added G-Sync support.

The only reason I switched back is that at the time sleep/suspend support wasn’t implemented yet. I think it still isn’t, is it? Granted waking successfully from sleep to a functioning graphical desktop is hit or miss for me even with the closed driver variant.

Yes, I’m on Wayland (Sway). I haven’t tested any native games. But I think RT/DLSS doesn’t care about Wayland or XWayland.

That being said, for now every game you run via Wine/Proton is running on XWayland (if one is on Wayland). They are in the process of merging code for native Wayland to Wine/Proton bit by bit. But it is going to take a while before everything is in place and Wine/Proton doesn’t need XWayland anymore. But as I’ve said, from what I understand this isn’t an issue for RT/DLSS at all.

Yes, RT Overdrive works. But it is VERY heavy on performance. I’ve got a 3080ti and had to sacrifice resolution in addition to turning down DLSS quality to get barely playable frame rates. But yes, it works and looks incredible. Edit: RT Overdrive really isn’t meant for graphics cards which are weaker/older than the upper spectrum of the 4000 GPUs. There is a mod on Nexusmods, which reduces the rays which are being cast. With it you can get a few frames back and you won’t really notice the visual difference unless you know what to look for.

Does the game have to be native or does it work through Proton?

Haven’t tried any native games. Proton works depending on the game. For example Cyperpunk 2077 works but RT in Witcher 3 doesn’t yet work (for me).

Is the performance comparable? Better? Worse?

Compared to Windows? Performance is worse but not by that much (for me on Nvidia). Depending on the game it is comparable. RT is very heavy on performance. You are going to want to enable DLSS or FSR.

Is it only working for AMD? Only for Nvidia? Both? (Neither?)

From what I’ve read they both work.

As already mentioned in another post it can be hit or miss. I think it works in most games by now. When Cyberpunk 2077 came out it took a long time for RT to work on Linux. Now it just works on most games I’ve tried. Witcher 3 being the exception since the update that introduced RT functionality. I’m on Nvidia. AMD should also work now. But supposedly performance isn’t great on AMD (just correct me if I’m wrong).