Hi there, @Maurizio_Febo and welcome to the Community 
The Code Block option lets you display the codes as the preformatted text, rather than a plain text.
However, unfortunately, it doesn’t transform HTML codes into interactive elements. We already have a similar idea on the Wishlist and you can upvote it here - Embed other widgets into Blog.
As for the CTA buttons, unfortunately, it’s impossible to implement a custom solution, but this idea is also on the Wishlist - CTA button for the posts
Regarding the post limit, please let me consult with the devs. I’ll report back tomorrow 