Is it normal for my iPhone and charger to heat up while charging?

Hello, is it normal for my phone and charger to heat up while charging? I’m using an iPhone 11, my charger is the new usb-c to lightning cable and 18W adapter. Although, it usually cools down after it reaches 80% but I’m still worried that maybe there’s something wrong with it. I tried using my old charger which is the usb to lightning cable and 5W adapter, and it doesn’t heat up.

[Re-Titled by Moderator]