iPhone 12 Pro Max not connecting to wifi or cell connection

My iPhone will connect to wifi but say it has 'no internet connection' even though literally all of my other devices have no problem connecting to and using the same wifi network. My phone also is having the same issue with cellular where it says it is connected but nothing is loading, and I have plenty of data usage left.

I've backed up my phone but I can't restore it because it needs to erase the phone first and Find My is enabled, and I can't turn it off without an internet connection. I tried deleting it from Find My via the iCloud website, but since my phone has no network connection it doesn't register that it's been removed from Find My. I've tried erasing all network settings and hard resetting my phone and that still does not resolve the issue.