Photos not in "Apps Using iCloud"
I recently noticed that I had lost access to some shared albums, shared between my wife and I on iCloud. When checking the Photos app, I realised that recent photos also hadn't uploaded to iCloud and synced.
On checking settings, going through Settings > My Name > iCloud, Photos no longer appears in the list of "Apps Using iCloud!" On my wife's iPhone it's at the top of that list. I've tried restarting, and everything is fully updated. Photos were working absolutely fine until around a week ago.
Has anyone encountered this before?
iPhone 11 Pro Max, iOS 13