There may not be an easy way to repair the damage unless you saved backups, but you can surely reset your server entirely to prevent yourself from crashing when connecting. Obviously you will lose everything practically on the server. You can always make a report if you have evidence of the grief and by who.
Keeping them complicated, but so you still understand them, and be sure to keep it as short as possible. Wherever something isn't necessary, don't have it.
This could be achievable through SKRIPT with a few addons. Minehut may still have the plugin DiscordSRV, can't quite remember but if it does that also has plenty of features. Not sure if you can start your server though. I doubt you can do this at all.