Apple ID signed in but not working properly after updated to IOS15.2

My Apple ID and iCloud are not working properly after I updated my iPhone to IOS 15.2:

If I go to Settings and click my Apple ID, the following issues can be identified:

1. some buttons are greyed out - Name, Phone Numbers, Email/Payment & Delivery/Sign Out
2. if I click 'Password & Security', it says 'Account Details Unavailable' and 'Get verification code' is the only option availible
3. if I click 'Subscriptions', it shows 'Cannot Connect'
4. iCloud storage info unable to load, and Manage Storage is not working
5. iCloud backup is on, but the 'Back Up Now' button is greyed out (I've connected to Wifi and my iphone is fully charged)
6. the trusted devices list (right above 'Sign Out' button) is not availible

I've tried restart and reset network settings but still can't fix this, and I can't sign out and sign in again becasue the sign out button is greyed out - I don't know what else I can do, and all of my other apple devices (Ipad/Watch) are normal. If anybody knows how to fix this that'd be much appreciated