It's not apples vs apples. Literally and figuratively. The I/O or board features on PC boards will eat power. So you will end up with a 15-30 W idle vs probably <5 for the Mac because they are effectively laptop board equivalents. I doubt the PCIe does much to the power, you need active chips to eat power. That is vs Intel.

AMD will add a bunch more watts to the idle number as their multi CCX CPUs just eat more power at idle. You'll be closer to 30-45 W idle.

AMD monolithic dies are more in line with Intel. IE the laptop/mini PC line will be nice and low.

The difference is vastly diminished when you add the display that's using 80 Ws. So that's 85 vs 100 W total system power? It just blows out total system power at idle and makes arguing over numbers less than 20 pretty meaningless.

Apple numbers are better in pretty much every way on power. But we're talking a handful of watts. Even at really high power rates it isn't going to add to up much.

Sources: I have a Mac mini and an Intel raptor lake desktop. I take measurements. And I have read various sources. This is my best information.