Solved for now...
Guess it was a bad idea to put an extra nginx proxy container in front of the app to tweak nginx config. A bit irritated that I don't understand why that broke only some http requests and not others. They all seemed to make their way through to mastodon.
I have a timeline again at least
Mastodon server for furries. 18+ only. Open to lions, their friends, nerds, and others.