Okay so, on my GMod server there is a hacker.
I’ve banned his SteamID and IP. But he has a VPN and keeps changing his IP as well as Alt-Steam accounts. So it’s impossible to keep him off, is there actually anything I can do?

Find the exploit that he is using and patch it. Post a list of your workshop addons here as well as your normal addons, and if you are, stop using leaks. Make sure to move your password out of server.cfg as well.

file.write a file that looks legit, check on client if it exists, if so, ban him

is this public or private? if public - i don’t know
if private- whitelist it to where only you and your friends can join.

I fixed it, it was in the ULX Utime module/addon.