I have this issue too and the referenced support article steps did not solve it. I’ve factory reset. I’ve updated to the latest iOS.
I spent two hours on the phone with apple support and my call was elevated, at which point I was finally told that there was a bug introduced in iOS 15.4.1 that affected iPhone 13 Pro and iPhone 13 Pro Max users who are on an e-sim. I was told there “is no solution” presently, short of going to your provider and asking for a physical SIM card (which doesn’t help those of us who use an e-SIM so that they can slot in an alternate SIM card for work/travel). The tech I spoke to also told me that this issue is affecting “thousands” of users. Though I haven’t seen many posts about it online, which I find confusing if this is affecting so many people on iOS 15.4.1+. The tech told me an iOS update would be forthcoming that would solve the issue.
I updated to iOS 15.5 yesterday and the problem persists. Not sure if anyone has heard any news about fixes for this specific bug/issue but I remain stuck unable to use iMessage from/to my cellular number. I can only send and receive from my email addresses.