It looks like a read error, so could be anything related to it. Permissions don't seem too likely, but possible. Could be a character in the path that some windows compontent doesn't like, or too long path.
You could try to see if moving Proton and the prefix of the game from one drive to another helps, but it just a wild guess, and comes with a risk of breaking other games. So if you are uncertain how to do it, I wouldn't recommend trying.
Sorry I couldn't help more.