Designer's Journal [Side Thoughts]: Nothing.tech Design Contest

I am actively forming an idea and concept for the Nothing Phone (3a) Community Contest, and while I don't plan to share my ideas just yet, I am at a loss for how to create a realistic mockup of my idea. I am definitely open to ideas. I'll drop the link for the contest info so you guys have a better idea of what I'm trying to create.

Link:

https://us.nothing.tech/pages/community-edition-start#overview