Accounts to block

Something like that could work, but I suppose that requires some more work to implement.

I wondered about how Wikipedia deals with that

https://en.wikipedia.org/wiki/Wikipedia:Vandalism
https://en.wikipedia.org/wiki/Special:SpecialPages ("Users and rights")

Difference is, this is a small community site where the wiki is a part of. IMO it makes total sense, and the most responsible thing to do, to take preemptive measures against vandalism/spam/abuse.

And delete the traces they put on the wiki.

Great! but how gross....

Which shouldn't.. https://www.msx.org/users/HaluChaiden is exit

Btw, always check "Recent changes". The main page is not the only one with these trolls, they create also a page about themselves: https://www.msx.org/wiki/User:RahayuBertha