Any third party lenses for Canon will have reverse engineered autofocus. I doubt Samyang has worked out the R mount autofocus yet and reverse engineering will never beat native autofocus for reliability. Also, don’t expect Zeiss to produce R mount autofocus lenses. Sony share their autofocus technology which is why that mount has autofocus lenses from Zeiss.
Shouldn't they be able to fake as if the lens is connected via an adapter, and use their existing EF implementation?