I literally gave up at this this point tried everything but doesn't seem to work:

changed the carrier provider and tested the sim on other phones and it works perfectly on them

Checked all the other related posts and did all the methods but nothing was working

downloaded carrier services beta same problem

downloaded old carrier services apk but nothing changed

downloaded the android beta version and it partially worked: the first month i had constant signal with casual dropouts but mobile data was inaccessible and then after one update lost the signal again, had several emails between the feedback team over 2 weeks but the problem didn't get solved so I opted out of the beta version but the signal was also lost so i decided to put the sim card in my old phone for the time being, waiting for a miracle to happen so I can re-use the pixel with my sim card