Why is my charging brick getting very hot?

Which "charging brick" are you using with your iPhone 14? If this power adapter is low wattage, for example, 5W, it may work "harder" to provide the necessary current to your phone while charging. This produces heat.

Alternately, the environmental temperature that your iPhone is in, while charging, may be a factor if it is too high.

Then it may still be possible that this power adapter is defective.

Is this adapter you purchased directly from Apple or an Apple Authorized Reseller? If so, and it is within 14 days of the purchase date, you can return it for either a full refund or for a replacement unit. After that, you would need to have an Apple Technician examine it to see if it could be a manufacturing defect, and if so, get a replacement for little or no cost to you.