Adapting Dark Victory as The Batman’s sequel would be a great way to introduce a new version of The Boy Wonder, not to mention maintain a tight narrative, bring back some villains from the last movie and introduce a few new rogues, whether they’ve been seen in previous Batman movies or not.
One rumor from earlier the year claimed that The Batman might include Robin, and if that’s the case, then there could already be some Dark Victory elements mixed in.
But remember, even though The Batman isn’t an origin story, Robert Pattinson’s iteration of the hero is still early into his crimefighting career, so the chances of him already having Dick Grayson by his side are incredibly slim.