Could The Joker Have Its Own Universe?

The recent ‘JOKER’ movie is a modern-day interpretation of the origin story of how Arthur Fleck became one of the worlds most famous villains to date. The movie references the Wayne family a lot throughout but could it be possible for this to be the start of a whole new DECU franchise kicking off?
The JOKER made a fantastic hit at the cinemas upon its release starring Joaquin Phoenix. It told a more modern-day version of the origin story of one of how Arthur Fleck became one of the most notorious super villains ever to be created in comic books. The movie showed the different events that occurred in Arthur’s life which made his sanity decline until his mental state turned into the Joker we all know today. With a deeper backstory to explore showing us what his family, social and work life was before it all happened.
But what is interesting about this storyline is that it references the Wayne family hugely throughout. It does seem that this Joker’s origins are tied with the Wayne family as his mother once worked for them and were involved in various altercations. Not only that, but Bruce Wayne when he was a child also makes several appearances and even encounters Arthur Fleck at the gate of Wayne Manor.
But what also surprised me about this was that at the very end of the movie the famous scene of the murder of Bruce Wayne’s parents plays which could be either an easter egg or a hint of what’s to come next.
When I came across this, I was surprised to see this scene even though this was a standalone Joker film. I was delighted to see this as its showing the complete story of how it all happened and came to be but I do wonder if it teases what it could lead onto.
It has already been confirmed that Robert Pattinson’s new Batman movie will not be apart of the JOKER along with it not being apart of the DCEU film but with the current ongoing expansion of the new DC universe, I believe that there is a prime opportunity for another universe to be created here. In addition to this, because of the multiverse theory hinted at all the time within the DC universe ever since Crisis on Infinite Earths it leaves another reason why this movie can be turned into a franchise where it includes the Bruce Wayne and Arthur Fleck from this movie facing off against one another in a historic battle as Batman and the Joker.
Done right it and with enough thought put into it I think that this movie can have its own franchise, even if it’s not technically part of the DCEU this time, and create its own version of the Batman world. With so many characters to recreate for its world such as Harley Quinn as Joker’s main accomplice. Having its very own Joker timeline, it leaves doors open to possibly tell the stories of other famous characters origins in the Batman universe or make the next few movies about this Joker facing off against an original Batman.