The ASRock Z890 Taichi wins in 5 out of 14 comparable specs, with 7 ties. Its biggest advantage is LAN (100% better).
MAG X870 TOMAHAWK WIFI wins in 2 specs (MSRP: 52% better).
Recommendation
Choose Z890 Taichi if you want the best overall performance — especially lan.
Choose MAG X870 TOMAHAWK WIFI if msrp matters more to you.