I hated the design of thread unroller apps on Twitter so much that I made my own a few years back called Spooler. It's still used by lots of people (I don't collect usage stats but people complain when it breaks).
https://tinysubversions.com/spooler/
All it does is: you give it a link to a thread, and it renders it to look like a blog post. It doesn't save or rehost the thread. It just makes it easy to read *in your browser* (for example, on a screen reader).
Would this be useful for Fediverse threads? Again this doesn't rehost content. It is basically just a 3rd party client for viewing threads. If you delete the thread, it can't do anything with it. People can't share the spooled post with other people, not really. The best they can do is send you a link to spooler with the url of the thread already in it and you press "spool" -- if you don't have permission to see the thread (bc you are blocked or whatever) it won't work
@darius I did not know about this but now I will definitely use