Ezra Miller isn't even close to a household name. But this story is dark enough to seriously trouble the movie. Grooming a minor? Running a little cult? Documented acts of violence, against women, no less! They can't do a press tour for this movie now. I don't see them putting out action figures with Ezra's likeness now.
They've probably spent too much on the movie to just bury it. But maybe it just gets quietly dumped onto HBO Max. And/or maybe they rename it Batman: Flashpoint and make some edits and cheap additions to justify it.
Amber Heard on her own would is no household name either. Don't expect to see her out promoting Aquaman 2. It's quite possible they reduce her role somewhat in the movie itself, but especially in the promotion. Luckily, she isn't the title character, so she's easier to work around when it comes to promoting the movie.