So I was wondering, I currently came up with two story ideas however both involve the same genre and fighting against the super natural. As a writer, is it okay for someone to write two different stories that's in the same genre but have different characte

It’s not that they get bored, it’s that they think they have seen what you can do. You create an expectation.

In comics, a lot of people start writing funny comics, like say, Dan Slott writing Ren and Stimpy, or me writing Simpsons. If we kept doing that, editors and readers begin to expect it.

I suggest making your projects as different as you reasonably can at first, unless you genuinely DO have a voice for one genre, by choice. Then, have at it. It worked okay for Stephen King!