What makes them currently not supported? Do your templates use blocks exlusive to the builders mentioned or are they just Gutenberg's default?

I don't personally use them, I've used Kadence in the past. However, I would assume they don't all offer the same blocks do they?

Would that mean once you support Greenshift, I already see it mentioned as an idea on your roadmap, you'll create templates that use templates using actual Greenshift blocks?

Yes, these templates are built with mentioned page builders, they are not built with default Gutenberg blocks.

Yes, Supports Greenshift means we create all of our templates for Greenshift that are available on our library https://wptemplatebox.com/library

Thanks