This may be unpopular, but after using Kodi and similar software for many years (and enjoying it!), I just gravitated back to the basics. Want to watch a movie? Navigate to it in my file manager and play it with VLC. Music? Just use Winamp 2 or Audacious. I realized I was messing with odd HDMI passthrough issues, database issues, audio sync, broken plugins, stressing about tagging, etc etc every movie night much more than just enjoying my media. My friend (Plex and Kodi user) had the same issues, we'd usually spend an entire beer at the start of the evening troubleshooting things. The most lasting thing from those days was setting up a proper NAS, first to house my media, then everything else.
The main thing I miss is wireless controller support, but KDE Connect on my phone has completely obviated that. It even integrates with streaming sites, youtube, VLC, Audacious, almost everything that exposes a media API. So I can sit on my couch or walk around and control my KDE machine with minimal effort. My PC audio playback even pauses when I get a phone call. If I need more control I can use my phone's screen as a touchpad mouse. You can't easily remotely compose playlists with this setup but I usually listen album by album or on global shuffle, and that's good enough for me.
Am I just old school? What are people's favorite "killer apps" for software like Kodi? Is it just convenience and I've have had bad luck?