Is The Batman still set within the DCEU? On a podcast, that was recorded back in July, director Matt Reeves stated, "Well, I have a vision for a way to do something with that character that feels like it resonates with me personally, and a perspective that can grow out into other things. When they [Warner Bros.] approached me, what they said was ‘look, it’s a standalone, it’s not part of the extended universe."
At face value, that seems a pretty clear indication that the film wouldn't be set in the same cinematic universe as Man of Steel, Batman v Superman: Dawn of Justice and Wonder Woman. Yet moments ago, Reeves took to Twitter to state that his comments were being misinterpreted.
Still, it's worth considering that Reeves didn't address whether his film would still star Ben Affleck...