iPhone 7 cannot connect to cellular network

My phone cannot use cellular network since last year,

ive tried every options and spent quite a reasonable amount of money,

I decided to try installing the latest version iOS which was supposed to fix the issue and everything went fine until I go stuck at “unable to verify....because you are no longer connected to the internet ” while my wifi is clearly connected.

this is frustrating

if you’d ask me out of of Apple, just say it nicely, I’m up in the middle of the night now trying to fix what’s not supposed to be an issue In other world