Most anti cheats cause problems with everything, the system is 20 years old as you said, it needs to be reworked. Like some users get banned just for playing on Linux…
Anti-cheat on the client should be an anti-pattern. Devs continue to make the mistake of imagining you can control the code running on someone else’s device and waste their efforts there instead of working more on the server (preventative) or analysis (punitive) side.
Anti cheat should be in game behavior analysis, its way more reliable when used together with report systems and manual checks.
But why allow rule-breaking game behaviour on your server in the first place?