I have exactly the same issue, since buying a new iPhone 13 and updating to iOS 15.1.1 (not bothering with 15.2 until they they fix the battery drain problems). Weirdly, I have the same issue with App Store on iPhone - i.e., no notification on my screen that there are apps that need updating.
Just been on the line to the most clueless Apple Support rep I have spoken to in 10 years (most are really good) - he didn't have any idea what to do. Anyway, I followed one piece of advice above (thank you) to reset location & privacy and it has worked. Let's hope the fix endures. I can't back up WhatsApp chat due to the app demanding that I have available a huge amount more iCloud storage than the size of the backup, which I don't. Frustrating.
Couldn't Apple and Facebook (which owns WhatsApp) between them, with their enormous wealth and resources, sort this out?!?