Photos do not sync from Windows to iCloud

Hi, I have 8,461 photos and videos on my personal computer (Windows 10). I installed iCloud for Windows and activated Photos on iCloud. I then moved all my photos from the computer to the Photos in iCloud folder. After several days of syncing, finally all the photos are in the cloud (at least that should happen, after I finish syncing).

My doubt is that on my iPhone and iCloud web I have 5,616 items (5,304 photos and 312). It's all synced, but I don't get to the 8,461 photos and videos that I have on my PC, and that are (supposedly) synced in iCloud.

Thank you very much for any help you can give me.