photos on macbook pro will not sync to my iphone

I've about 10,000 photos which I've imported to my 2022 MacBook Pro.

I also had about 8,000 songs, which I installed in Music.

Both Music and Photos work on the MacBook Pro.

I setup a new iPhone 13 mini, and the music files all transferred from the Music app to the iPhone.

When I tried to do a similar thing with the Photos app, about 200 images only transferred and installed on the iPhone.

I've turned off wifi (which I don't use, as I have my Mac setup with a ethernet cable).

I've tried pressing the sync button in the Finder window when the iPhone is attached but all it does is go through the 5 steps of syncing and that's it. None of my photos appear.

I've no idea how to get these photos into the iPhone (it was simple in iTunes/iPhoto on an iMac, so what's the problem with Photos on a MacBook Pro.