Update to iOS 14 and 15 - Cellular doesn't work - iPhone 7/Verizon

An update was apparently forced to my phone yesterday, because it restarted on its own. After restarting, cellular would't work. The phone reported an update failed. I retried the update (for the latest version of iOS 14) several times while on WiFi - it failed each time. I then followed Apple's directions to update via my laptop. After backing up my phone to the laptop, I tried to update. This resulted in my phone being on iOS 15.1. Still no cellular. Under Settings>Cellular, it says "an update is required to use cellular date on this iPhone." Under Settings>General>Software Update, there is no available update.