I had been having trouble getting meaningful results from the fediverse on Google, and after seeing this post, it seems I'm not the only one. So, I created a site that helps search the fediverse in your search engine of choice (it currently supports Google, Bing, Yahoo, DuckDuckGo, and Dogpile).
It currently only searches the top 15 lemmy/kbin instances due to search engine query limits (I'm not sure how to fix this short of making my own search engine), but I've tested it and it seems to provide access to the majority of fediverse content.
If you have contributions or ideas for improvement, feel free to check out the project here or shoot me a message. Hope this helps people! :)
https://fedi-search.com/
Edit: Update in progress including improved search queries and support for Mastodon/PeerTube (Google only, unfortunately)