While the Joker was teased at the end of The Batman, The Penguin made it clear that he’s a villain worth working up to, and there are plenty of other worthy options that deserve the spotlight. So, hear me out, the DCU is preparing to introduce big heroes like Superman, and the Elseworlds projects are already covering stories around Batman, such as The Penguin, and even the Todd Phillips Joker movies. While the Joker is evidently one of the villains who get the most attention from the Batverse, it isn’t the same as being the only worthy villain whose story is interesting.

https://screenrant.com/the-batman-2-joker-dont-want-after-the-penguin/