This happened to me, although luckily I managed to turn off registration after about 80 signups. I did have email verification enabled but noticed that every single email address was fake/the email bounced, so they havent been able to verify the accounts and post.
I have now enabled applications (along with email verification) - does anyone have any opinion on using captcha instead of applications? I feel like captcha has already been defeated by bots.
Fwiw the captcha support in lemmy is probably going away soon. It needs to be reimplemented into another database table (or something like that) anyway. Given that it is too hard for many humans, too easy for many bots, and devs are slammed with work, makes more sense to delete as a first step