Same problem here 11 Pro Max! I just updated to iOS 14.3 yesterday and earlier I charged my phone and after 20mins when I checked, it was very hot to touch. First time it happened to me and as I was looking for some answers I came by this topic. My phone somewhat became a tad bit slow too, that it’s unusual because I get bored waiting. You know when you’re used on doing your routine, you’ll notice a difference when something is off. When I first got my phone I had no problems, charging nor overheating (nothing!) and I loved how fast it was. Then I had updates and the same thing is happening with my battery, draining fast and went to draining so fast (same usage). That’s the first thing that I noticed. Does anyone have an answer? Don’t tell me that my charger might not be the “original” or whatever bs they are saying coz they are! I got it from Apple itself when I bought the phone! No apps were running while charging, so cross that out. To add to that I still have 330 gb available capacity, so it’s not my storage that is slowing it down.