I gave up on the Kbin/Mbin style entirely - it sounds nice to Federate with both Lemmy and Mastodon, but I don’t like the interface.
Can you not do personal user instance blocks like you can in Lemmy as of v0.19.3 half a year ago? That would be an absolute deal breaker for me too. On Kbin.social though it was not an issue bc they were defederated at the instance level.