Experienced "Cellular Issues" - Updated to iOS 16 - Phone no longer works

I have an iPhone 11. I woke up on Tuesday morning with a notification that read something along the lines of "your phone is experiencing cellular issues." The Cellular section in Settings is turned on. My bars are continually searching for service, I never see "No Service." It's constantly trying to search. I cannot make any calls. The phone works via wifi, basically an iPod Touch.

I was on the phone with my carrier for an hour and a half doing all the "turn it off, turn it back on again" stuff and nothing was solving the issue. I went to the carrier's store and got a new SIM card. That didn't help either. Time for a new phone, I guess.

I go to trade it in and the trade in value is $0. Cool. I buy a new phone outright and try and fix the phone myself to get trade in value.

This is all in the same day. I go home, restore the iPhone to factory settings, completely wiped everything. After 30 minutes or so, I go to set up the phone manually, with the famous "Hello" screen. Choose my country, wifi, then I get to a screen that says "Unable to Activate" - "An update is required to activate your iPhone" "Learn more at apple.com/support"

Ok so doing a factory reset hurt the problem even more and I cannot access my phone. Support has not been helpful. I don't know how to revert to a previous version of the software without having to do some black magic things. Just stuck with an overpriced piece of metal that I cannot trade in any funds for. Has anyone been in my situation before? Any advice would be helpful, thanks!