UnknownUnknown
Follow-up: No issues spotted, works out of the box
This is a follow-up to my previous report, so first things first: it turns out that the Windowing issue I reported last time was a user error; I failed to notice the button meant for confirming the changes in display settings specifically. The windowing does, in fact, work both on Windows and on Linux. My bad.
As for performance, here comes the only change to my system since my previous report: I changed the PRIME Profile on NVIDIA X Server Settings from On-Demand to Performance Mode. This change just about got rid of all the small FPS drops I experienced during my previous test (drops that don't occur on Windows, as I found out while testing more on Windows); while there are drops to 59 FPS, they are far, far rarer, and the FPS counter actually stays at 60 FPS quite consistently now. I believe these tiny drops are a driver issue rather than a Proton issue, as having OBS Studio record the screen while playing dropped my FPS by over 10 even though my RTX 3060 (laptop version, driver from nvidia-driver-515) did not go anywhere near 100% usage as far as nvtop could tell. In any case, no complaints on how the game itself works on Proton!
Works out of the box without any Linux-specific issues spotted (tested on 6.3-8 and 7.0-6, controller support verified on the latter too)
Fullscreen and Windowed display modes don't work; changing the setting does not change it from the Borderless Window setting. It seems like it doesn't save the change to that setting at all. Based on a quick test on Windows, this appears to be a bug in the game itself rather than a Proton/Linux-related bug.
The game consistently stayed over 50 FPS at the High graphics preset, sometimes dropping around 1-6 FPS down from the 60 FPS cap, not that I noticed any difference beyond the FPS counter's number changing. Initially (while testing on 6.3-8 which I had on by default for some reason) I had a couple of drops to around 40 FPS but those did not occur once I started playing properly, so I believe they were just starting hiccups rather than notable graphics issues. Verifying whether or not the small frame drops are a Linux-only thing requires further testing with Windows (and verifying which GPU is getting used on my Linux system while I play, the AMD one or the Nvidia one).
