ProtonDB. If there's nothing there, then I resort to running Steam in the terminal to see logs.

1. Protondb
2. Different proton version
3. Restart steam in terminal and look at what it logs (permission problems are quite frequent multi-user system)
4. Die

You have already done most of what I would do, but here is my list:

• Try another Proton version (in my experience Proton 6 seems stable and sufficiently different)
• Check ProtonDB if this problem is known
• Read the logs in the command line output
• Try both steam-native and steam-runtime (maybe this is only an Arch thing?)
• First back up, then delete the entire protonprefix (~/.local/share/Steam/steamapps/compatdata/<GAME-ID>). THIS WILL ALSO REMOVE ALL SAVEFILES OF THE GAME!
• Use an Xorg desktop environment instead of Wayland

ProtonDB.

Run from terminal and see what went wrong.

If you’re using a launcher with built in logger, refer to that (I’ve seen one on lutris, not Bottles, unsure about heroic).

I go on protondb and see if people regularly have problems. If not I check to see if someone has the same GPU. Then I try whatever trick they have there. Then I try switching to an X11 session instead of wayland.

If there's a launcher like rockstar I search for that specifically.

I usually don't have to do this at all, but this is my system for the rare hiccups, in order.

• ProtonDB
• Are they using an incompatible anticheat?
• Different proton (usually one a few versions behind esp if it's an old game, maybe GE, more than that isn't useful)
• Verify installed files through steam
• Make sure my mod load order isn't crap (if applicable)

.

• Check if the game launcher actually points to the correctly named file + rename / change the exe if not (usually this gives an error box saying the file is not present)
• Uninstall + reinstall (esp if previously worked)
• Broad internet search for game + linux distro
• Launch options I've used for other games (PROTON_USE_WINED3D11=1 often is my first tried)

.

• Protontricks, tell it to use a different version of windows
• Uninstall DLC, launch vanilla once, reinstall DLC (yes this has worked more than once for various weird issues, no i don't know why)
• Backup personal data files, + delete all installed files / workshop files + verify installed files again
• Wait for someone smarter than me to figure it out / a system update that addresses it / new proton and check in a few months

PROTON_LOG=1 in the launch options

First I typically see if other Proton versions work, like ProtonGE or Experimental. That tends to fix quite a number of issues.

If still not, to ProtonDB I go. Often if I can't find a solution there it's hopeless.

I have two machines with different hardware.

Sometimes this helps if it runs on one vs the other

If it's something not on ProtonDB I will try installing common dependencies like the Visual C++ Runtime and .Net.

Change proton and proton-ge versions. Other than that, pray that it fixes itself if a few days / weeks.

More often then not it's because of an update and I reboot.

I know, I know, don't ask, it works.

Otherwise I just spam different Proton version until something magically works.

If it doesn't work with normal proton or bleeding edge proton experimental, then I refund.

Proton Hotfix and Proton Experimental

I had this issue where a game wouldn't launch at all and there weren't any useful logs. I don't know how to use wine to launch the game without steam so I didn't do that. I stead I pretty much reinstalled kernel and dependencies. I don't know what went wrong or how that fixed it but it did.

I think it had something to do with drivers.