Smart Playlist Syncs, but None of the Songs Do

I don't have an Apple Music subscription, and these are mostly not purchased songs.

Deleting the playlist on my devices and trying to resync them results in the same problem - playlists appear, but no songs.

Those are the exact steps I am following, and yes, the songs in question are present and playable on my Mac. And I made sure they are not unselected in the desktop Music App.

Often times, these songs do sync in other smart playlists, it's only a few select smart playlists where absolutely nothing syncs, and it's the same ones every time which has me completely frustrated and confused as to why it is happening. Many of these are playlists that used to sync just fine but lately are not doing so.

To clarify, most of the songs on my library were either ripped from CDs that I own or purchased from other mp3 vendors. They play just fine in Mac and they also play on my devices. In fact, they will often sync to my devices via some Smart Playlists, but not other Smart Playlists. In the Mac, the Smart Playlists with the songs are all there, but on my device, the problem Smart Playlists will be there but not the songs within that list.

So I did that, and now even the newly created playlist won't sync at all. Before the playlists would sync on the phone but the songs would not appear. Now the playlist itself does not sync, even though I selected for syncing.