You can try going to https://app.plex.tv/desktop#!/settings/web/debug and clicking on the red Restore Defaults but note the message there:
All Plex Web settings, including home screen customization, will be reset and restored to their default state. NOTE: If settings sync is also turned on, settings on other Plex Web instances may also be reset. Use with caution.
That might fix your default view of the Live TV / DVR screen.
