The CPU is fine, as is the GPU, it supports DirectX 12 natively.
Although it is on the weaker end of the spectrum, and you may have even more issues once the new Graphics update is out.

Check this Official link for Mac system requirements:

https://eu.finalfantasyxiv.com/system_requirements/

On that page if you click on the Mac OS tab it lists what OS and version is supported.

I'm unsure how to rollback drivers on Mac, though it seems like it must be a software issue.