Why is the same issue with iOS 11.4.2 is happening to my iPhone 7 with iOS 13.3.1??

My iPhone updates on its own when I don’t update it for a while, and continues the update whenever I turn it back on. It seems like the auto download keeps cutting on after I turn it off, and it seems to have more problems with it when I don’t update it! Now that my phone updated to the latest iOS, it’s been buggy. My phone won’t let me make calls, it won’t even let the microphone work for Siri and other apps!! I have an iPhone 7 after my iPhone 6 messed up and wouldn’t let any sim card work on it. I don’t really know if it’s my carrier or not, but I have had sprint on both phones. Please for Gods sake, fix the bugs!!!