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…
Manually downloading HTML posts would be more difficult, but it might be possible by parsing the data export you can download from Facebook
Yeah, I was going to suggest a data export, as this will often give you a handful of files, most importantly would be a CSV containing all your posts. It would probably be relatively easy to automate the process with that file.
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.