iPhone 16 Pro overheats while charging and stops at 80%

My iPhone 16 Pro bought November last year, gets over heated while charging and stops at 80% when not in Airconditioned area, or outside, when in AC it charges 100%. Also when am using youtube for continously 30 mins or more it gets over heated and tough to hold in hand or keep in pocket. Apple Service Center Unicorn, Apple Authorised Service Provider Ahmedabad, Says the 80% charging issue is there because my charging limit was set to 80%, (then howcome it charges 100% when in AC) now talking about getting over heated when using youtube or gaming for more then 30 mins, he said its normal cause motherboard. gets heated. Am surprised that a phone like iPhone 16 Pro can get heated just by using 30 mins continioiusly? This is the 2nd time am visitng there. 1st time they said the default OS installed on my phone is not good so he changed it to the Service Center version after that I started facing other issues like on Phone Calls apps, it always says that these many number of calls are missed, and keep on adding, even if I have seen them and called them. few features don't open in settings or take more then 10 to 15 seconds to open, the guy said all is normal. I have been using the iphone continiously since iphone 6 to iphone 16. I thought of recording him, but recording not allowed in service center. I have spent almost $1150 for this phone in India, and its a good amount here just for a phone.

[Re-Titled by Moderator]

Original Title: My iPhone 16 Pro, gets over heated