https://www.theguardian.com/world/2023/nov/03/online-vitriol-could-undo-decades-political-progress-dutch-deputy-pm While I'm particularly sympathetic to her, as they've pushed for some good policy, such as opposing the chat control:

"anonymous accounts" Curbing the use of anonymous accounts would be quite problematic for the freedom of expression. Also, I don't think this actually worked out when they tried it in South Korea.

"doxing" Maybe, something could be done about doxxing?

"hate speech" Ugh, the problem is that the particular argument which people use for this is one which tends to also be used elsewhere (and that is both bad for expression and often inappropriate as well).

I think you'd be better off breaking up Facebook into several smaller social networks. It would be very politically difficult but it doesn't involve fiddling around with matters of content.