Multiple issues on iPhone 12 Pro Max after updating to iOS 17.4

My phone has also done this since updating yesterday. Notifications won’t clear even when read. Phone still vibrating randomly small little buzz’s. I’ve now lost all contacts. iMessages had to be relogged into. Photos wouldn’t delete to allow for more storage. Logged out of my banking app and now cannot log back in. All my apps seem to be reset and are asking me to login or taking me through tutorial stages even when I’ve had them 2 years. So frustrating!!

Both my wife and my phone has moments of flashing screens, flashing through different apps, phone calls that drop and something else pops up and its place. Everything was fine until I did the update - I updated my phone and then my watch and have possessed since I updated them both. My watch just called my coworker on its own.

I’m having issues with having to reenter P/W’s and turn Face ID back on

I’ve had trouble with my Messaging app since updating to 17.4 on my 12 Pro. It just freezes randomly and there’s nothing I can do. Closing the app doesn’t help. I just have to wait until it unfreezes, which it does eventually.

iOS updates aim to enhance user experience, boost security, and fix bugs rather than disrupt core features. Message alert issues after updates might stem from underlying, unmentioned factors. Updates won't typically alter personal data but may refine settings or features. Backup before major updates for safety. Review Apple's update details and backup advice for a smooth process.

Kindly consider checking your settings and addressing any device issues before attributing the issue to external factors. This could be a pure coincidence that the iOS update affected the iPhone functions.

Before initiating a standard iOS update, it's advisable to create a backup. Have you completed this step? If yes, proceed with the restoration from the backup.

See what each update does: About iOS 17 Updates, About iOS 16 Updates, About iOS 15 Updates, About iOS 14 Updates, About iOS 13 Updates, About iOS 12 Updates, and so on...

iOS 17.4.1 is out, try installing that version and see if it fixes your issue.