All apps disappeared (even App store)

I have the xs and I just used my macbook to update it to iOS 17. As soon as the update was done I realised that all apps were gone. Even the phone app is missing. iMessege, contacts app, app store app, all gone. Storage says it is all still there, but there is no way to access them. I tried restoring via backup, but iCloud won't let me accept the Terms & Conditions, so I can't use it at all. I also can't connect the phone to the macbook anymore, cause it won't accept the "trust" verification, even though I click it on the phone. The phone doesn't even recognise the sim card. Any ideas as to what on earth is going on and how I can restore the phone to its former (useful) glory? Even to ask this question I had to use my gf's mac, cause I can't use my apple ID on it. Cause of the double verification system that uses my phone.