This fediverse at least. AT Protocol, used for bluesky, supports nomadic identity. Instead of accounts being @user@domain.tld, they attach your domain / home instance / whatever, to a DID. You can read more about it in their various spec pages but here’s the one for DIDs.
If we find instances infested with bots and unwilling to deal with them, we defederate them. It at least makes it more difficult to mass-infest the network with bots if we have basic things like captcha, email verification, and applications implemented in all the major instances. cough