[reconnecting]

This works because you had synchronised your iPhone with your Mac previously. If you start with an empty Photos library and phone, it is impossible to put all the photos on the phone and thus transfer them to your Mac.

[fizwidget]

No, I’ve downloaded the entire library to a new Mac. It worked fine.

[reconnecting]

Thank you. Yes, indeed. I found out that Monterey is not syncing iCloud due to "Performance".