Someone else in the comments here suggested the „Infuse“ app on iOS. It can use multiple backends including jellyfin, plex, but also sftp etc. Cannot speak for its daily use as I just installed it myself, but looks good on the first glance.
Infuse also does not support multi profiles on Apple TV. Which makes it essentially useless for multi-user devices.
Infuse is a very decent _paid_ app. That’s what’s going on. It lets you play with the interface and test its integration with your services/media. But to use it you pay either a subscription or a one time fee. Very reasonable in my opinion.
Now, I am aware that it might just be the selection of codec and resolutions I happened to try are all paid-only. But the way it went, I indeed felt "cheated".
Yes, Infuse may be a very good _paid_ app, but I do not like it the way it tells you that is a _paid_ app.