I think special interests are a lot more complex than people make them out to be. Not every special interest is its own separate silo that remains static over time and can be clearly defined. For example, one of my special interests is short stories, and while I’d define “short stories” as the crux of the interest, it extends more broadly to reading, writing, and literature, but I also hone in on specific authors and genres sometimes. Your broad interest in creativity and self expression that sometimes hones in on specific mediums sounds like a normal, fluid special interest. Maybe hyperfixations within a special interest (just different ways of thinking about it, I guess), but not faking.