The Jellyfin app itself doesn’t support Direct play, which ruins it for me straight away. Not to mention it’s just the web version in an app anyway.
Swiftfin app is fine, but it doesn’t have PiP, when you open a series, the episodes don’t show up until you select the season again. (There is an issue on GitHub for it and it’s been there for a year now https://github.com/jellyfin/Swiftfin/issues/653 ). You can’t mark episodes as watched, no support for some audio codecs, sometimes wrong audio/subtitles picked and other little things. Still prefer it to the other one but yeah…