I dont have much to add other than I am an experienced admin and was dismayed at how vulnerable Lemmy is. Having an option to have open registrations with no checks is not great. No serious platform would allow that.

I dont know of a bulletproof way to weed put the bad actors, but a voting system that Lemmy can leverage, with a minimum reputation in order to stay federated might work. This would require some changes that I’m not sure the devs can or would make. Without any protection in place, people will get frustrated and abandon Lemmy. I would.