cannot connect iPhone 6s 15.4.1 to Macbook Pro Catalina 10.15.7

Hallo. I'm probably just stupid but I used to plug my iPhone 6s into the McBkP and it would show up in iTunes. Now I plug in and the McBkP says it requires a software update to connect to the phone - do I want to download and install. I do - the third time I tried this it appeared to download and then the window vanishes. I appear now to have only music not iTunes in the dock.

All this started because my iPhone is full- I have 106 GB of photos - and no cloud. I wanted to remove some of the photos to free up space BUT not delete them.

Would upgrading to Monterey help or just add confusion?

Now I don't know what to do.

I would be grateful for any help please.

Thank you