According to sources, the Joker & Harley Quinn movie, along with the DCEU solo Joker project, aren’t happening anymore, or if they are, they aren’t a major priority.
That’s pure speculation, but for now it looks like the Joker & Harley Quinn movie and the standalone DCEU version of a Joker project are done for the moment.
The DCEU might be done with Jared Leto Joker movie projects for the time being.
It appears that the Joker & Harley Quinn movie, along with the DCEU solo Joker project have “fallen by the wayside” at Warner Bros. The studio has a massive success on its hands with James Wan’s Aquaman and looking to move forward, away from the connected DCEU projects.