Cellular issue detected, I restored my iPhone now I can't activate it?

I started getting cellular issue detected notification after i updated my ios version and this continued i would lose service and my phone would start restarting on its own i contacted apple support and they said i should check for software update on itunes i checked and there was none and decided to restore my iphone after my iphone was restored and the hello page lit up i swiped chose my language, selected my region, then the quick start page is shown and i select "set up manually" it goes to this might take some time and jumps to another page that shows: ⚠️ unable to activate, an update is required to activate your iphone, learn more at apple.com/support

And i can either select to go "back" or "shutdown"

What in hell should i do?