The ASRock Z890 Taichi wins in 8 out of 14 comparable specs, with 2 ties. Its biggest advantage is M.2 Slots (200% better).
B550 AORUS PRO AC wins in 4 specs (PCIe x1 Slots: 100% better).
Recommendation
Choose Z890 Taichi if you want the best overall performance — especially m.2 slots.
Choose B550 AORUS PRO AC if pcie x1 slots matters more to you.
