Welcome to ChooseYourStory!
To start, I would like to say that the fact that you know what interests you is a great milestone in writing - even if they don't become the base of your future works, they could very well be used to add intricate detail. For the most part, I'd say that the community here is active and supportive.
Occasionally, a contest would be hosted. To participate, all you have to do is simply write a storygame that meets the site's requirements. A great place to start is Mizal's Best of 2019 contest, which has no specific themes and a distant deadline. Contests, for the most part, are a great way to start producing content if you don't know where to start.
I am looking forward to seeing your stories. Best of luck!