Our instance is federated with hexbear, lemmygrad etc. I want to be resonsible for what I see and block, I’m really not a fan of defederation unless it’s a last resort (i.e. CSAM or other illegal content).

Yes, that’s pretty much our take on it: we’ll defederate CSAM (and nonce-adjacent) instances asap, those with lax registration tend to become havens for spammers and trolls, so there is usually a wave of defederating, then someone reaches out to them, it gets sorted and we allow them back in. That tends to be the regular defederation and isn’t controversial. Defederating, for example, Hexbear over, for example, trolling would be a bigger deal and we’d try and speak to the other Admins about it before any permanent banning.