I just want to say in case you didn’t see my other replies, that probably won’t work out as well as you think, because the way instance blocking works it only blocks the communities. User content still comes through.

From Join-Lemmy:

Users can now block instances. Similar to community blocks, it means that any posts from communities which are hosted on that instance are hidden. However the block doesn’t affect users from the blocked instance, their posts and comments can still be seen normally in other communities.

So regardless of the uninformed people suggesting this, it isn’t a solution to this issue, especially the hexbear spam problem, it’s not an alternative to defederation, and it never was, fact is Lemmy isn’t a free speech platform, people and instances can and will be banned and moderated, people who don’t like it just need to either deal with it or go elsewhere.