Hello @The-Foxon, issues with games run with Proton are being tracked in the Proton issue tracker, so I've transferred this issue report.
Please add PROTON_LOG=1 %command% to a couple game's launch options and attach the generated $HOME/steam-$APPID.log to this issue report as a file. (Proton logs compress well if needed.) Also, please copy your system information from Steam (Steam -> Help -> System Information) and put it in a gist, then include a link to the gist in this issue report.
@kisak-valve I supplemented my post above
Yes, this is true /hdd/2/ - this is a hard disk in NTFS format, but I previously installed games there, and they ran smoothly.
P.S. Proton is installed on a disk with ext4
Still, now that I have moved both the game and Proton to a disk with ext4, the problem has been solved. It is strange, although before that, when the game was installed on an NTFS disk, it was quietly launched.
When you start any steam game using proton, their status changes to running for a few seconds, and then it's ready to start. Proton Experimental and 6.3-4 versions were used for the launch.
Steam info
Proton log 1:
Proton log 2:
Steam console log:
UDP: Added logs for Proton and system information from steam