Ok, this might be a dumb question, but is it really technically possible in any way - even a convoluted one, like manually downloading HTML pages from Facebook? - to mass import posts from one’s Facebook into Mastodon or Friendica instead of painstakingly copying them one by one? I’ve got a 10+ year archive to port and it’s a daunting task to go through them…
The FB export files have everything (your posts, comments, reactions etc) as html files and images/videos.
Getting it from those files into parts that can be uploaded somewhere else will take some work. Either with programming if OP has knowledge, or copy-paste.