I am creating a Hero section with the main CTAs (Link + phone).
The link button should be blue und both buttons shall stay stacked on top of each other.
This desired State can be seen in the first image.
When I click on preview or visit the published site the button becomes black and they are side to side
I believe you have solved the layout part as I can see the buttons stack on top of each other in preview and live site.
For the color mismatch, you probably have an interaction setup on the CTA Main element which also sets background color based on the hover interaction. You might want to double-check if the initial state of background color and hover out action has the background color set to blue instead of black there.
For some reason, I am not able to load the interactions to give you a detailed suggestion, but what I mean is, you can select the CTA Main element and head to ‘Interactions’ tab and make sure to select the version as ‘Classic Interactions’ as highlighted in the screenshot below.
You will be able to see what interactions are setup for this and my guess is there is probably a background color property being set in those interactions which you can modify as per your design requirement.