... of building a new system low. Why may a high-end motherboard, especially gaming motherboards, have less or more of these integrated features?
Begin first with the box. Reading is not highest potential now. There are many videos of you tube with exactly what you are considering.
wifi is a 12 dollar item. Video going to 4K is available with a 1900 dollar monitor. This is old but so far out of most peoples reach.
One high graphics driver is 2600 dollars.
unfortunately you asked for direct answer rather than conversational answer.
I will simply say on closing the power supply is more important than which mother board.