iTunes iOS 18 Missing Most Purchases

I upgraded from a iPhone 11 Pro to an iPhone 16 Pro, and restored from a backup stored on my laptop. Since then I've had serious trouble restoring my music library on my new device.

If I try to download purchased albums from the iTunes store, only a small fraction of albums I purchased are available for download. If I try to find the album in the store, I'm prompted to repurchase it.

I do not have iTunes sync turned on due it having issues where it would randomly delete copies of songs I ripped from my physical library from my device. I do not have Apple Match either. I am on a family copy of Apple Music, but I prefer not to use it in favor of my physical library and iTunes store purchases.

Why can't I access music I purchased? None of it was hidden by me.