@famarast,
I have requested a developer license for Divi to confirm this, but my gut is telling me that this will not be possible. This is because in WordPress, the Admin Dashboard and Frontend are handled very differently and the Divi Builder Elements are designed around being used on the Frontend of the site.
Even if we were to force the Theme CSS and Divi’s Shortcodes that the Builder inserts into the Page Content to work within a Client Dash Admin Page, it would likely not look how you would want it to because of the rest of the WordPress Admin Dashboard styling and structure conflicting with it.
I would recommend instead setting up some type of private page on the Frontend of the website that only a specific User Role can see (Using a Membership plugin or something similar) and then adding a Custom Link to their Client Dash menu to it. That would allow you to build out the page as you’d like using the Divi builder while still placing the link within their Admin Dashboard Menu.
I’ll update this ticket with my findings regarding using the Divi Builder to make Admin Pages in Client Dash if/when we get a developer license to test with, but like I said, I do not think that approach will work out.