the other release Plex Media Server is built around an AppImage and Xenial library.
it depends of the integrator Knapsu and has not been 100% optimised for Bionic Ubuntu
May be it runs well for you, in this case do not consider this one.
This release has been fully compiled with Ubuntu1804 Libraries and is more stable than the AppImage one
it runs in TV mode Fullscreen by default (to exit with keyboard push CTRL+Q)