Turning Off 5G-Auto and Siri

My iPhone 13 Pro Max started protesting almost the very day I updated to iOS 15.1.1. My battery inexplicably depleted quickly, and it ran burning hot to touch. I could charge it fully before bedtime, leave it by the bedside; by the time I wake, the battery would be at 20%, and it would be super hot. That was bollocks. I had to resolve this quickly. This could completely kill the still-new battery if I'm not careful. 

I ran through the gamut of help pages to sort out what could be the issues, as well as criticisms of the latest iOS updates and the various bugs flagged by users. I turned off everything that could be turned off. Apple Support could only suggest this page for my reference. WALAOEH. I had Apple Support remotely run diagnostics with me to ascertain if it's a hardware issue. Nope. It's clearly a software issue. Apple Support suggested that I send in the phone to the Genius Bar to resolve the issues. I decided not to do it and try to sort it out on my own first. My last resort is to restore this phone to factory settings. If all else fails, AppleCare will replace my phone, especially if other users' phones don't throw up similar issues. 

It was highly frustrating because I didn't know what else to turn off. It isn't any singular app that's causing the issue. The fact that the phone heated up in standby mode both on cellular data and wifi didn't make sense. It violently heated up every day. I couldn't be using this phone set in airplane mode half the time! A few days later, I realized what happened. 

• I rarely call up Contacts on the phone. When I did, it couldn't stay on any one name. The page kept flickering. It couldn't remain still for me to even read the address.
• Running a check on Battery didn't flag any abnormalities last week. But over the weekend, when the phone burnt down from 70% to 30% in less than an hour, it revealed that Siri had used up 40% of the battery operating power. WHAT. I don't even use Siri! And I didn’t recall enabling it to even wake at ‘Hey Siri’.

To have the battery burn down this fast, the phone must be searching for something, which explains why it ran in the background while on standby mode despite me disabling Background App Refresh and Wifi Assist. I checked under Cellular Data, and made sure the phone latched onto 4G and not 5G-auto since I'm not subscribed to 5G. 

Then I went to turn off all of Siri's search functions, especially for Contacts. I didn't enable Siri, but somehow, the search functions were enabled. I disabled everything. The phone stayed cool and calm for the next three days. The phone had been most obedient all week. Please stay this way, FFS. I had no issues with iOS 15.1. This iOS 15.1.1 is giving me a ton of bugs. Can they patch it soon? Otherwise we'll all roll eyes when the next major iOS 15.2 update rolls around.