In moving to Mastodon from X a few years ago, I didn't want my content to be owned by a platform, but I also just don't have it in my to write blog posts, posting threads bit by bit works better for my brain.
So my solution was to write a script that took that any thread I start with a certain hashtag in it, and threadreader-style mirror it to a basic HTML page on my own website[0]. That way, if my Mastodon account ever goes away, all the threads I actually put any effort into are preserved.
[0] https://kalleboo.com/microblog/ I'm intro retrotech so this site is designed/constructed so aside from the videos it works fine on a Mac with a 25 MHz 68040 CPU. All the data is stored in a big JSON file so I can re-format it whenever I want.