ASRock X570 Taichi works flawlessly with installed ASUS Thunderbolt X3 thunderbolt expansion card.
If in your location there is no ASRock Thunderbolt 3.0 AIC R2 card in stores you can use nearest available from ASUS or Gigabyte GC-Titan Ridge AIC (proof). Everything works just fine without any drivers/dancing/etc: hot plug, power delivery, thunderbolt and usb-c 3.1 devices, as usb-c external monitors (like ASUS ZenScreen MB16AC) and Apple Cinema Display thunderbolt monitor (everything work: usb, sound, network, webcam).
ASUS Thunderbolt X3 card is cheaper and it has only one thunderbolt port. ASRock and Gigabyte have two thunderbolt ports.
