This happened to me too! I have an iPhone X (Canada) that was working fine before the download and after the download, my data/cellular network just disappeared, nothing even appears in the "cellular tab" in settings. It is a completely blank page. My phone is basically an ipod touch except its a barely a 3 year old iphone X. I also went to my carrier and was told it was a sim card reader issue which can be fixed. I also chatted with Apple Support and did a diagnostics test and was told that the "baseband module" was the problem and can be repaired and just as she was about to start suggesting solutions, the chat got disconnected and a different apple support member took over the chat and immediately told me that this issue could not be fixed and the phone would have to be completely replaced and promptly told me that "a total unit replacement for an IphoneX out of warranty is $719" Side note* the iOS 14.1 update came out today and my phone refuses to update this, when it gets to the point of actual installation I get prompt of "im no longer connected to the internet" (I am) and i have done all necessary steps including deleting the update from iPhone storage. Apple must acknowledge this is a software problem and fix this issue!