itunes library is different on iphone and PC. HELP

Only have one itunes library, i.e. one sign in, etc.

Used to sync with USB cord between PC and iphone.

iphone had subset of PC itunes music library.

Computer crashed, and had to reinstall windows10 and then reinstall all apps.

Now, the itunes library on my PC has NONE of the music that is in the itunes library on my iphone.

I went and downloaded everything supposedly that Apple could find in my itunes library onto my PC.

No help. Still whole artists and albums gone from my PC, which is supposed to be the repository of all my music.

I do have an icloud account, which works fine for calendar and notes, but doesn't want to do anything with music that isn't associated with a subscription to Apple Music.

How do I get the part of my itunes library that is on my iphone back onto my PC?

Help!!!!