I was looking for a place to share my two favorite Mastodon and Lemmy clients, they are called Voyager Connect Boost for Lemmy and Moshidon for Mastodon (if you are really serious about privacy I recommend Connect still)
(the official Mastodon app works fine though, you just can’t follow new hashtags from it)
They are very good, try them out sometime 👍 (I’ll update this post whenever my opinion changes)
I am using the iOS App Store version of Voyager, and it is excellent as well. It finally displaced Memmy for me, which is also a good one to try.