confused by music sync'ing options adding apple music to my 'manual sync' library
All my music is on my Mac (w/Catalina). I sync the entire library to my iPhone manually. It's a mixture of stuff I've purchased via iTunes and stuff from CDs which are not on iTunes or Apple Music. Sync'ing has issues (dupe playlists galore) but the tracks are at least in sync as far as I know.
I've now subscribed to Apple Music for 6 months after switching to Verizon. My understanding is that if I turn on "Sync Library" on my Mac and iPhone, Apple Music will sync the two but ONLY if the track is in Apple Music which will not be 100% of my library. Without turning on Sync Library, my understanding is I can stream Apple Music but not download tracks to listen offline.
Can I continue to manually sync my library as well as turn on Sync Library? Which one takes precedence and would Sync Library remove stuff it can't find in Apple Music, and the manual sync keeps putting it back?
Or do I have to pay for iTunes Match to make this situation work?
iPhone 11 Pro, iOS 13