Same here: After updating my iPhone SE (1. Gen) to iOS 13.7 I had issues with the cellular connection for a few days, which then somehow disappeared. I hoped that iOS 14 would fix this bugs, but in fact it made things worse. I tried every suggested solution including restoring to factory settings. Apple support tried to convince me that it's a carrier or hardware issue, but my provider tells me otherwise and the same carrier is working fine on other phones and also my phone worked smoothly before the 13.7 update.

So far iOS 14.0.1 didn't change anything for me neither. Cellular connectivity still doesn't work at all. Wifi is not as reliable as it used to be before the 14 update. I tried every solution suggested here and elsewhere (including Apple support).

Country: Germany Model: iPhone SE (1st gen) iOS: 14.0.1 Carrier: O2 Although I already posted two times here, I want to add something to Desmox' comment below. Everyone should think twice before applying the factory reset. I had the same problems as Desmox some weeks ago activating my phone afterwords, but kept on trying (via my Mac) and after countless attempts it finally worked. BUT: This didn't solve my my problems with cellular connectivity at all. Neither did any other suggested solution. I tried them all. Currently the phone keeps searching connection nonstop (draining the battery), although I removed the SIM card to use it with another phone, which works perfectly fine. I can't even change any cellular data settings, since the menu shows nothing but "error". This is definitely a Software issue or at least a Software provoked issue, although Apple tried to tell me otherwise.