iPhone 12 heating

I’ve been using my new iPhone 12 since two weeks now, I find that it’s heating. While charging, up to around 80% it heats up and later cools down on its own. It is also heating up during normal use (not as much as It heats during charging though)

I read some blogs that iOS 14 gives heating issues

I visited a service Center nearby, they say that since it has metal body, heating is common. Also they told me that iOS 14 has no relation with the heating and an upgrade to iOS 15 won’t help.

Since it is a new phone, it is a matter of concern to me. Any thoughts on my concerns?