Syncing music including digitized cd’s

I have read that syncing my Library in Music app on my MacBook Pro (it uses my original iTunes library, and iTunes as an app no longer appears on my computer) will “show all music you’ve added purchased and uploaded. The music on this computer will appear on your other devices after syncing with the cloud.” …according to apple. However according to users, this only applies to music currently obtained from the Apple Store, it will REMOVE all the cd’s I have digitized, only keeping what I have purchased from the Apple Store. Is this still the case? How can I integrate my personal downloaded and digitized music collection easily and safely in Music, which is the app I used the most for listening?

at the moment I do not sync music on my MacBook Pro, because it houses all my digitized music and non apple downloads… I only listen to that music on the MacBook Pro. However it would be nice to access this on all my devices, or at very least, the iPhone. Does anyone have definitive experience or knowledge in conserving digitized and downloaded music which in not apple-sourced, and safely including it in a synced apple Music library? I have a Music subscription. Thanks!