Integration between custom post types and page builders

Hello,

I've questions regarding integration between custom post types and page builders.

I've a page builder named Phlox, bought in Envato market.

I followed your instructions, which are wonderful. Then I created, custom post types and taxonomies. I tried to change typography in Gutenberg, like: sizes, type colors for mobile and desktop. However, there is no place inside this editor to do that. Then, I tried to change it through Phlox page builder, but it didn't do anything. I wrote to their customer support regarding this issue. They wrote to me that this is a third-party plugin. Hence, it couldn't be customized through their page builder.

What I'm asking are:

1. Are they right or is there a problem with their page builder?
2. Are there other page builders which I can customize typography, button, etc through custom post types? If there are, can you give some names, and what do you recommend to use?
3. Are there other ways rather than CSS (or any other coding) that I can customize typography inside custom post types?

Thank you

Ori