Hello @kisak-valve, nice of you to reply so quickly.

Hello @anohren, defeating Steam's general sanity checks can not be supported.

It's been noted. Although I can't say after being referred to Github for support by Steam Support and receiving an overwhelming zero replies to an issue even after having isolated the problematic component, that I consider any other parts supported either.

That set aside, you may have some luck setting the immutable attribute on the script with chattr +i.

Thank you, that seems to work! Good call.

Actually, now Steam is just wasting lots of time doing nothing whenever I try to launch a game.

Doesn't work -- no support. Can't do much other than to write steam off as unusable on linux.