Just a little feedback: one of my most hated dark patterns in design is when you give the user the impression that they can try out your website but they actually can't. That's the case on your website: there is a text field making it seem like you can give your site a spin, but as soon as you hit the submit button, you get a pop-up telling you that you have to sign up first. And that after I already spend some (admittedly small) effort to craft a sample text.

I personally hate that pattern, and my default reaction is to immediately close the tab.

Perhaps you could change the landing page to avoid that negative first impression?