Thank you for your engagement here. I too have heard this request before, however I have nothing new to report regarding the release of a CTA API.
The HubSpot Community Ideas Forum is the best place to share feature requests, and I'm afraid the discussion here hasn't had the visibility it deserves. The product teams regularly monitor posts and generally prioritize ideas which have the most engagement from and greatest potential impact on users.
I found this existing idea requesting a CTA API. If you would like such a feature added, please upvote and comment on the post. I've already upvoted it.
I recommend including as much detail as possible per these best practices. The more the product teams understand a feature's use case, the more accurate they will be when scoping the feature.
Thank you for your understanding. I will close this topic to maximize feedback on this idea.