Update: LOL
Just as i already thought; it’s the database. I have to “optimize database” at least once a day to make plex run smooth.
I’ll cronjob the cli command to optimize-database from now on.
But i would strongly suggest to kind a “fix” the scheduled optimization to allow “daily”.
This could have saved me around 2 Years of frustrating Plex-expierence, just because the database couldn’t keep up.