How do you pick a niche if you have no hobbies or interests. I'm slightly exaggerating, but there's nothing I can say, "yeah I'm an expert at that". (Besides what my employer pays me to do, but I don't want to cross contaminate).
You have to pick a hobby or interest.
It's OK if you don't like that hobby or interest, almost no one likes things once they work at them hard enough to make money