Yeah as others have pointed out, the big problem with trying to use fanart to get more views/followers is that there's virtually no crossover. And I don't just mean there's no crossover between your fanart and your original art, I mean there isn't even any crossover between your Fandom A art and your Fandom B art.
For example, if I was interested in Persona for awhile and drew a bunch of it, then became interested in JoJo later and drew a bunch of it, I wouldn't even retain the bulk of my Persona fans. It really is that tangential in many cases.
So to echo virtually everyone else, I would suggest only drawing what you love and if the thing you love best happens to be your original characters, draw mostly that. Whatever little fanart you genuinely want to and enjoy making then becomes bonus art for your fans to know more about your personality.
Then they'll like it regardless of the fandom because they're a fan of YOU.