Honestly good question. 1 thing I am 100% sure is that it will look like 9999k tv quality anime. Like even better than Violet Evergarden (if you saw the freaking graphics and physics and shii of that anime, you know damn well what I'm talking about). Not just the people, but the grass, skies, animals, stars etc.

I think my inner world would contain everything from magic, science, gods, aliens, and anything amazing and fantastical. Now there will maybe be some stuff made from dark aspects for sure something terrifying and alluring.

Copy and paste the real world, but give everyone outside the United States superpowers. Once an American emigrates to a new country and denounces their American citizenship you gain superpowers, but being on US soil temporarily neutralizes these powers. Conversely, anyone who emigrates to the US and claims citizenship loses their powers until they return to their home country. Through loopholes, Americans can't go to war with other countries using superpowers, but every other citizen of the world can.

I'd love watching the cognitive dissonance that follows. "We live in the greatest country on Earth! Our military is so great, no country could ever touch us, not even with superpowers!"

My inner world would be everything and the totality of anything related to me! Imagination, Interests, Emotions etc!

I’ve mentioned this whenever BIW comes up but essentially my inner world would be similar to Scala ad Caelum from Kingdom Hearts 3

Entities I create (mostly humanoid) would live in houses around the island with my castle being much bigger and spacious inside than outside. Also underwater, there would be a city under the surface of the water.