There are too many. The other day I saw the latest flash movie. It's the second? Third? Fourth? I don't know because they don't put a number and I don't care enough. Too many stuff referenced other movies or series making watching a bit of a hassle. Is this just unknown and will be told later for making the movie interesting, or it's because the audience is supposed to having watched 40 hours of previous works?

If they really need to push a new superhero movie or series every 2 months, their stories should be self contained, at most separated in a trilogy. Not an infinite parallel universe constantly self referenced that needs a guide that tells you which content you need to watch and in which order.