I apologize if this is old news, but I just noticed it. It looks like Kagi has added Fediverse Forums as a default Web search option.
I tried, years ago, I think their federated approach to building a database and crawling are cool - but at least the last time I checked, the actual search algorithm was just too bad. It often gave me completely irrelevant results and seemed very susceptible to spam sites gaming Search Engine Optimisation.