MEG ace is a stronger board than the CH7 but the difference on ambient is probably very low or nonexistent due to the PWM used , doublers, and the powerstages used (both are using IR powerstages and IR PWM).
MSI ace has a chipset fan (with fan stop) and cooling the 3 x M.2
The promotion makes the Ace relatively competitive: https://www.msi.com/Promotion/I-Love-You-3000-AMD/
You have to consider what you want from X570. NvMe at PCIE 4.0 speeds is pretty much the major difference. The CH7 is a good board.