I have the same issue. Since updating my iPhone X to iOS 14, the cellular connection goes to "no connection" about every hour, and requires a hard reset. I've gone through every troubleshooting step including rebuilding my phone twice, to no avail. I guess I'll wait for Apple to figure out where QA dropped the ball and actually fix the underlying problem. Oh, and the next Apple Store appointment is too far in the future to schedule....whatever that means.