Just sub to things you care about and ignore the rest. I almost never look at all, and if I do, it’s only on my local instance, so I pretty much only see stuff I opted into.

I recommend you do the same. Or just block the handful of communities you really dislike and continue using all.

Defederation is how we get silos like beehaw, which is antithetical to a federated platform. Defederation should know be used if an instance causes active harm (e.g. users constantly troll and admins are unresponsive). Having stupid content only impacts those who look at it, and it’s easy to block, trolls impact everyone.