The MSI MAG B850 TOMAHAWK WIFI wins in 8 out of 14 comparable specs, with 5 ties. Its biggest advantage is PCIe x16 Slots (100% better).
PRO B860M-A WIFI wins in 1 spec (MSRP: 35% better).
Recommendation
Choose MAG B850 TOMAHAWK WIFI if you want the best overall performance — especially pcie x16 slots.
Choose PRO B860M-A WIFI if msrp matters more to you.
