Hello,
Recently came across this and wanted to share it here. If you want to target the styling on secondary CTA only, you can do so by targeting (for example):
.HitchhikerProductProminentImage-secondaryCTA .HitchhikerCTA.
In this example, I am specifying the secondary CTA on the Product-Prominent Image cardtype first and then targeting the .HitchhikerCTA element to make sure only the secondary CTA styling changes for this specific card type.