AHa - thanks to reading other replies here I stumbled into the fix for me. Runing iOS 17.0.2 (upgraded from 16.3 two nights ago) and noticed last night photos taken with the iPhone SE (gen 3) were not appearing on the MacBook photos program. But when I went to the Settings-->Apple ID-->iCloud screen it immediately informed me I had to agree to the terms and conditions (apparently big brother wants to be bigger) - after dutifully complying the sync proceeded, even as I type this note. So, there's that.