You need protontricks and the numeric game id.
From a terminal, run
protontricks game_id winecfg
And it will pop up a config window for the proton instance for that game. From there, you can tell it to pretend to be windows 10 instead of win7. You should only need to change it once. (Well, maybe again if you change proton version, or maybe not. I’m not sure how steam manages its wineprefixes)
If you go into the game’s preferences in steam, you can modify the launch command to enable logging:
PROTON_LOG=1 %command%
Then when you launch the game it should put a log file in your home dir. That will hopefully give a clue as to what the problem is.