Music Artwork not sinking with iPhone correctly/Apple Music not able to grab correct Artwork or Artwork at all

I just bought a brand new MacBook Pro 2023 and have been trying to get the artwork to sync with my iPhone 14. The music that I bought from Apple iTunes way back when seems to sync with the correct artwork, no problem. But, I have hundreds of CDs that I own that I imported to iTunes on my previous MacBook Pro that I own. These are CDs that I own, and went through the process of adding the artwork myself because iTunes at the time did not have the correct artwork or the artwork at all. I'm now running into the same problem and when I add the artwork to Apple Music, it will not transfer to my iPhone. It is a bit frustrating, and I don't know what to do. I also do not subscribe to Apple Music. The files that I have are either from CDs that I own or from music that I purchased in the past. There is also the problem that when I've asked Apple Music to add album artwork, it either grabs incorrect artwork, duplicate artwork, or no artwork at all for various albums. I could go through the process of adding the artwork manually to the Apple Music, but if it's not going to transfer to my phone, then is seems a bit of a mute point, as well as would also be a bit frustrating. If anyone else has run into this problem and again has a suggestion, please reach out. Thank you so much for your time and consideration.