Okay, well to balance that anecdotal information with some more, let me put some of those bad points listed in context with what my experience has been on Debian 12 Stable with an RTX 3090.

• Proton is great, and is really impressive, but you still must download several versions to expect running everything you want, and you must do trial and errors to find the most efficient version for you (fortunately, ProtonDB helps a lot)

Somewhat true, but protonDB is so accurate that I think I have only had to trial and error 1 or 2 games ever. Downloading multiple proton versions isn't a big problem as they aren't too large, and I have only ever needed either the latest stable release, or the experimental release. As far as actual game compatibility goes, when I moved to Linux I looked up every game in my steam library in proton DB to see what I was working with. The result was that:

95 of my games ran natively on Linux. 31 of my games were rated platinum. 73 of my games were rated gold. 12 were rated silver. 3 were rated as bronze. 3 were noted as unplayable.

• Nvidia drivers greatly improved recently, that's true, but you still have to download the latest beta drivers to run games through gamescope, and they are not on the official pacman repo, so they won't upgrade automatically.

You have to add 1 repository for the drivers and then it upgrades when you upgrade as normal. This is like a 2 step process of editing a text file and then running one command. I have never had to use gamescope.

• Now, let's talk about performance. Yeah, I have an Nvidia card. Yeah, I know it's bad for Linux. But that's what I got, and I bought it very recently, so I won't buy an AMD card for Linux now. When you talk with Linux users, they will always say that performance in games is way better than in Windows. Maybe that's true in some games, but I'm afraid that's only the case for AMD users. With an Nvidia card, the best you can get is the same performances as in Windows. And that is when you're lucky. Then, if you want shiny things like HDR, or DLSS frame generation, you MUST use gamescope, and it will have a cost in terms of performances. And you will need trials and errors to get everything you want.

Performance on some games is better through proton and this is true even with my NVIDIA card. This is largely because where you lose performance on emulation, typically you are making up for it in leaps and bounds because Linux is not running 1000 telemetry processes and stuff in the background like Windows does. I have only played one game where the performance was noticeably worse. I don't use gamescope at all. As far as I'm aware DLSS/HDR work fine (running armored core VI on ultra graphics for example looks and runs great and the settings seem to be enabled). As I said before, I only ever had to trial and error 1 or 2 games.

• That said, don't expect other shiny things like RTX HDR in desktop, frame gen out of games that natively support it, DLDSR, and many other things like that, to work in Linux. In fact, everything that is available through the Nvidia App or the Nvidia Control Panel won't be available in Linux. You must be aware of that, because that's very cool features you'll likely never (or in a very distant future maybe) see on Linux. You won't be able to use Lossless Scaling neither, and there is no equivalent in Linux - even in gamescope, at least for now (but maybe that'll come, I don't despair of seeing this happen in the future).

Parts of this statement are just straight up not true. When installing the drivers, you also install the NVIDIA Settings application which does not contain all settings from the NVIDIA control panel, but a subset of them. RTX HDR in the desktop for example does work, but it is just dependent on the window manager. Here is another reddit thread stating as much. I assume the OP of the thread you linked doesn't really know what they are doing. If you want a windows-like experience you probably would be using plasma. Also I'm pretty sure lossless scaling has been a feature in protonGE since 2021, so if you really needed it for a game, you would just install that proton version and use its FSR feature there. I mean, this is stuff that comes back top link when I google for "Lossless scaling linux NVIDIA". The OP really doesn't seem too dedicated to looking up their problems.

• Hardware compatibility too, while very good, and even more so with Arch based distros of what I heard, is still a work in progress. For example, I didn't found out how to make Dual Sense haptics work in The Last of Us Part II Remastered. Everything works, even adaptative triggers, but haptics won't work. I know it has to do with the impossibility for the game to find the gamepad's sound device, and there is many workarounds. I tried ALL of it, but still, it doesn't work. That took me several hours to try it, and that's what finally made me give up on Linux for gaming for now.

My PS5 controller including its haptics work natively on debian. I didn't even have to install any drivers or software for it to work. I just plugged in and started playing. I think it just has to be wired for haptics, or whatever you are using for wireless needs to be capable of supporting the controller and its haptics.

So pretty much all of these issues seem to be related to the OP not really investigating their issues well, or not understanding where to go to change settings, or not understanding how their package manager works.

This looks fine.

I have a massive library of various games, and three years in I haven't really come across any cases where I want to tear my hair out.

If ProtonDB says a game doesn't work, you're not gonna tweak your way to having it run. If it says it does, and it didn't run right away with no problems, you can usually just apply the fixes other users have found, and be off playing your game.

In fact things are often simpler than on windows, because all the fixes have been gathered on protondb. While on windows you have to google-fu your way to finding someone on reddit or the steam forums who has the exact same problem, and also figured out and posted the fix.