I do not know whether anybody else has already said this, but Lemmy could really use a feature that would allow individual users to block instances. I think it could have spared some of the defederation word wars that have been going on lately, since that would be an individual choice rather than a collective one.
Just a thought.
Lemmy-client app can did this now. If you use iOS, you can try memmy. This app can filter keywords or instance.