iPhone syncing unselected music and videos
As far as I can tell, I have the relevant sync settings selected.
Sync only checked songs & videos
Selected artists, albums, etc.
The only checked item on the Music tab among the artists, albums, genres, & playlists is a playlist that I maintain for my phone.
I suspected that this is a metadata issue because I did some spot checking of the tracks, and I haven't found any so far that were purchased thru iTunes. However, not all non-iTunes tracks are synced despite the settings.
iPhone 7, iOS 15