i had the aorus x570 before the crosshair viii impact in the same setup and had exactly the same experience as you.
the problem is probably really the board in general because we are 4 people here with the same board and same temps.
I haven't changed the thermal paste so far.
i've got exactly the same hardware with a gen 3 nvme. except that the chipset reaches a much higher temperature and the fans are whiny.
so you're saying asus included a noisy pch fan just to save 2-3C°?
i might actually do the same now. 75C° under load seems perfectly fine i guess.
I would probably not even care that much about the chipset temp if we could just control the PCH fans which is currently not possible. I just really hope asus will include this in a future bios update.
I've got this motherboard in my case with a U9S cpu cooler including a second 92mm noctua fan.
Now if you've got this board, you know that they placed the chipset fans directly where the noctuas should be. I already moved the 92mms away from the rear case directly to the cpu cooler...