Looking for a lightweight but working anti-cheat for version 1.15 I can take a paid plugin or free plugin! Thanks everyone!
I tried Matrix. It had too many false positives, and generally just didn't meet my needs (I need to turn off individual checks in a specific world). So now I'm using the NoCheatPlus that Phoenix just referenced: https://ci.codemc.io/job/xaw3ep/job/NoCheatPlus-1.15-Xaw3ep/