I’ve seen a handful switching to Substack as well. I’ve been experimenting with that platform lately and I like the post editor, lots of tools but not overly bloated, it’s pretty good. My only complaint so far has been that a lot of History/Academic Substacks seem to be pushing for the paid tier and so hide a lot of their posts behind a paywall Patreon style. Because of that Mastodon has been my favorite since the Twitter exodus.