Like I arrive on the homepage, to give it a try, it is like "go, just type the description on the park and we will generate it", so I spend time crafting my requests, and when you validate, you arrive on a fucking login-registration-wall.
I'm not against needing users to be registered, but that it something that you should tell upfront before users waste time trying to use your tool.
And the dark pattern doesn't stop there, behind the registration-wall, you have another deceptive practice, a dynamic "loading status" like "connecting the dots", "mixing the palette", ... that is running to give the impression that the generation is running when it is not at all until your register.