iPhone 12 pro max won't sync with itunes

I recently purchased an iPhone 12 pro max, and thought I left the store with a complete transfer. I now realize that I don't have access to my Apple Music library; I've tried simply syncing my library on the iPhone, I've tried syncing it with my computer (I only have one computer, a pc, but I have tried multiple connections). I get a greyed out "sync" when I drop down from file>devices, but the button appears active when I'm looking at the viewing pane for the iPhone. However, when I click the button, it immediately resolves with absolutely no change. I've been a long time Apple customer mainly due to iTunes and Apple Music. I've carefully curated playlists over the years. They're all gone. Considering the price of this new phone, and the fact that music is WHY I came over to Apple in the first place years ago, this is very much a reason to leave Apple if it's not resolved quickly. Music is life, and I need my playlists back. I've been working on this for multiple hours, I've tried everything I've seen on the chat boards, etc.--NOTHING is working, and this is beyond unacceptable.