Whenever I try and sync the photos to the mac photos app it crashes to desktop probably because I have like 60gb of unsynced photos.

That’s terrible. My library is 100GB and works fine so may be worth trashing the machine and trying again when freshly installed.

So you have to buy a Mac to get your files?

I already have a Mac. I'm trying to get rid of it.

You can download icloud for windows as well. And slowly download shit off the web UI.

Web ui is broken the downloads always error out for large icloud accounts in my experience.