I’m totally frustrated by this - my iPhone has now ‘not been backed up for 24 weeks’ it shouts to tell me every 5 mins - I have done manual backups but because I don’t use the latest OS on my Mac mini and my home WiFi is a shared network between residents, I cannot log in to sync as such - it just begins to tell me that it will take 2 mins, 500 mins, 35 years lol! I can’t get it done in Macdonalds either as someone above says - as a result I have hundreds of duplicates photos and videos and a permanent petulant ‘this phone Has not been backed up.. blah blah blah’ every time I use it - I’m so tired of it - I’ve used Mac’s for over 25 years and this is just **** - my 50gb of cloud storage is almost used up with the continual duplication - some 400 photos and 30 videos now mushroomed to take up 15gb alone - I know!!! And all because I can’t afford a new Mac and live in a new build with shared WiFi - F F S in very big letters loool - new iPhone, loads of space, latest IOS etc etc - sucks teeth - even went into apple store and they didn’t want to help ....
Sounds like all you need is a proper network connection to the cloud. Are McD and your home the only useable WiFi networks for you?
luckily Apple did not listen to that nonsense and gave us larger batteries which are amazing.