There are, but it’s complicated. Doom (2016) for instance - it doesn’t handle the very large Vulkan swap chain that’s possible on some modern graphics cards, crashes on start-up. Someone patched Proton around that time so that Doom would start; the patch was later reverted since it broke other games. Other games based off of that engine - couple of Wolfensteins, Doom Eternal - have the problem fixed in the binaries, and so run on up-to-date Proton, but depending on your hardware, only a few specific, old, versions of Proton, will do for Doom.
Regressions get fixed - that’s okay. Buggy behaviour which depended on regressions that got fixed - that’s a problem.
There are, but it’s complicated. Doom (2016) for instance - it doesn’t handle the very large Vulkan swap chain that’s possible on some modern graphics cards, crashes on start-up. Someone patched Proton around that time so that Doom would start; the patch was later reverted since it broke other games. Other games based off of that engine - couple of Wolfensteins, Doom Eternal - have the problem fixed in the binaries, and so run on up-to-date Proton, but depending on your hardware, only a few specific, old, versions of Proton, will do for Doom.
Regressions get fixed - that’s okay. Buggy behaviour which depended on regressions that got fixed - that’s a problem.