Problem Syncing CDs from iTunes to iPhone

Hello there,

Recently I cancelled my subscription to Apple Music and started using CDs as my weapon of choice for listening to music. I imported all of them to iTunes, which worked great, but now I'm running into problems putting them on my iPhone 7 to listen to. Whenever I try syncing over Wi-Fi, it puts most of my music on the phone. However, many of the songs (it seems to be random, no artist or genre in particular, just some songs or entire albums) do not copy over. The closest I can figure out a pattern in is it doesn't like Muse or twenty one pilots, and some specific U2 songs. In iTunes, they are grey with the dreaded dotted circle next to it, and they are grayed out on the phone. Upon syncing, I get the message "Some of the items in the iTunes library, including '...' were not copied to the iPhone '...' because Apple Music songs cannot be copied to an iPhone."

Immediately after I click "Ok," I get, "The iPhone '...' cannot be synced because it cannot be found," and the phone disconnects, requiring me to unplug and replug it in several times to get the phone and computer to talk to each other. When I try to play the grayed out songs on my phone, I get a message saying, "This song is not currently available in your country or region."

Obviously there is something wrong, since I am no longer using Apple Music as a base for music, and all my sources are American copies of CDs. I have tried manually moving individual albums over from iTunes to iPhone, but that only got me so far, as iTunes wouldn't let me drag many of the albums into my phone. My phone, computer, and iTunes are all updated to the latest versions. Would anyone have any advice as to how to move these songs and albums to my phone?

Thanks