Take a photo on your iPhone and wait for it to sync on your Mac. You might get lucky and it syncs nearly immediately (which is still typically a minute or so, even if your phone and Mac are on the same network and have gigabit internet). But you won't know when. And it might not be immediate.
Both sides will tell you they're up to date. You can't force a sync. They'll be synced when Photos is ready, not you. And if that's ten minutes or more later? So be it. You'll just deal with it.
This is a very good example of a disruptive bug that destroys the ability to work. I’m making a document on my laptop and using the phone as a camera to take pictures, I am working on, now. Same WiFi, same person, same cloud, inches apart. No work.
Take a photo on your iPhone and wait for it to sync on your Mac. You might get lucky and it syncs nearly immediately (which is still typically a minute or so, even if your phone and Mac are on the same network and have gigabit internet). But you won't know when. And it might not be immediate.
Both sides will tell you they're up to date. You can't force a sync. They'll be synced when Photos is ready, not you. And if that's ten minutes or more later? So be it. You'll just deal with it.