Yes and I do have an account on an instance of both (although, the one that used Sharkey transferred over to Cherrypick) along with Matrix, but I don't use them very much though.

The problem I have with Mastodon, Sharkey, Cherrypick and any other similar platform (including Twitter, Minds, and Bluesky back when I still had an account), is that I've never found them to be useful. Every time I post to any of these platforms, either no one ever seems to actually acknowledge my posts or I get responses that aren't helpful. While my posts and comments still sometimes still get ignored, I've found Lemmy (and Reddit back when I still had an account) to be much more useful and helpful.

As for Matrix, I do still log in sometimes but I've never found any reason to actually use it.