Isn't Truth Social (Trump's thing) technically part of the fediverse, since it runs on Mastodon? I don't know if they're a far-right equivalent of lemmygrad since I haven't spent time on either but it seems like a fair parallel.
Personally I'm not a fan of eager defederation. I'm skeptical of the benefits of deplatforming and I think that casual use of the banhammer, even if the subjects deserve it, is corrosive to our own ability to think clearly.