When I launch Plex Media Server the icon appears own the menu bar briefly. Selecting the icon shows “Server is Starting…” in the menu for about 20 seconds, then the menu disappears. The app is no longer running. I only recently reinstalled the app.
I would try deleting the com.plexapp.plexmediaserver.plist file , restart computer then try to launch server again first. It will treat it like it is a new server install as far as ID. Info on file location can be found here https://support.plex.tv/articles/201105343-advanced-hidden-server-settings/
Looks like there is database corruption causing issues.
Oct 07, 2020 12:22:42.760 [0x700008b5b000] ERROR - SQLITE3:0x103262608, 11, database corruption at line 65066 of [bf8c1b2b7a]
Oct 07, 2020 12:22:42.760 [0x700008b5b000] ERROR - SQLITE3:0x103262608, 11, statement aborts at 9: [UPDATE metadata_items SET extra_data = replace(extra_data, 'at%3AreadOnly=', 'pv%3AreadOnly=') WHERE extra_data LIKE '%at^%3AreadOnly=%' escape '^'] database disk image is malformed
Oct 07, 2020 12:22:42.760 [0x700008b5b000] ERROR - Exception inside transaction (inside=1) (../Library/DatabaseMigrations.cpp:209): sqlite3_statement_backend::loadOne: database disk image is malformed
Oct 07, 2020 12:22:42.778 [0x700008b5b000] ERROR - Exception thrown during migrations, aborting: sqlite3_statement_backend::loadOne: database disk image is malformed
Oct 07, 2020 12:22:43.907 [0x700008b5b000] ERROR - SQLITE3:0x103262608, 11, database corruption at line 65066 of [bf8c1b2b7a]
Oct 07, 2020 12:22:43.907 [0x700008b5b000] ERROR - SQLITE3:0x103262608, 11, statement aborts at 10: [select max(max(metadata_items.changed_at),max(metadata_items.resources_changed_at)) from metadata_items] database disk image is malformed
Oct 07, 2020 12:22:43.907 [0x700008b5b000] ERROR - Database corruption: sqlite3_statement_backend::loadOne: database disk image is malformed
Oct 07, 2020 12:22:43.907 [0x700008b5b000] ERROR - Error: Unable to set up server: sqlite3_statement_backend::loadOne: database disk image is malformed (N4soci10soci_errorE)
You mentioned in first post this is a reinstall. If you are starting from scratch then I would try deleting the entire Plex Media Server folder that is in Application Support or move it to desktop or someplace to backup https://support.plex.tv/articles/201941078-uninstall-plex-media-server/