When using the flatpak version of Plex desktop on Ubuntu, if I full-screen the video using “f” and I forget to un-full screen it before the video ends I cannot. Instead I get to the info page in full screen and need to play another video so I can un-full screen the desktop player.
I think that “f” and esc or double-clicking the mouse should enter/exit full screen from any screen in the Plex desktop player.