You appear to be running into a (now) known issue recently discovered where, in version 1.18.7.x, PMS will crash if the iTunes plug-in is enabled:
If you’re able to disable the iTunes plug-in (Settings → Plugins) try that. If you can’t run it long enough to access settings, you may need to install an older version. If you’ve been updating via the client applications you should have a folder with older updates at:
/Users/username/Library/Application Support/Plex Media Server/Updates
Relevant entries from your logs:
Feb 22, 2020 22:16:57.894 [0x7000013ac000] INFO - iTunes: parsed library in 2.3 seconds.
Feb 22, 2020 22:16:57.894 [0x7000013ac000] DEBUG - Loading com.plexapp.plugins.itunes is complete (success=1)
Feb 22, 2020 22:16:57.896 [0x7000013ac000] ERROR - Couldn't rename file "/Users/admin/Library/Application Support/Plex Media Server/Plug-in Support/Databases/com.plexapp.plugins.itunes-new.db-shm" to "/Users/admin/Library/Application Support/Plex Media Server/Plug-in Support/Databases/com.plexapp.plugins.itunes.db-shm": No such file or directory
Feb 22, 2020 22:16:57.896 [0x7000013ac000] ERROR - Couldn't rename file "/Users/admin/Library/Application Support/Plex Media Server/Plug-in Support/Databases/com.plexapp.plugins.itunes-new.db-wal" to "/Users/admin/Library/Application Support/Plex Media Server/Plug-in Support/Databases/com.plexapp.plugins.itunes.db-wal": No such file or directory
