When news first broke of Micheal Keaton joining The Flash as Batman instead of either Ben Affleck or even Jeffrey Dean Morgan as Thomas Wayne, many became doubtful that Affleck would return at all. In a shocking turn of events, though, Affleck was later reported to return as Bruce Wayne in The Flash in a minor role.
While the role is small, many fans are hopeful that it will act as the perfect send-off to Ben Affleck's portrayal of the character. However, previous rumors of HBO Max wanting Ben Affleck to return in the cowl are resurfacing, meaning that The Flash might not end Affleck's role as The Dark Knight.
Entertainment writer @BlackMajikMan90 reported that those in charge of HBO Max, depending on the success of Justice League Director's Cut , are interested in Ben Affleck returning as Batman, but that "the ball is in his court."
In a later tweet defending this report , they said "If I hear something or I'm told something I will share it."
WHAT THIS MEANS
At the very least, @BlackMajikMan90 is confident that a source close to them relayed this news. However, keep in mind that even if Justice League Director's Cut on HBO Max is a success, it doesn't mean that Ben Affleck would return as Bruce Wayne for an HBO Max show or movie.
As @BlackMajikMan90 said, it would still be entirely up to Affleck on whether or not he'd want to return to the role again after his minor role in The Flash . HBO Max could offer him a lucrative deal and he could still turn them down. Additionally, just yesterday, The Flash producer Barbara Muschietti seemed to imply that this movie would "...in a way, it restarts everything and doesn't forget anything."
So, this potential project on HBO Max could be its own self-contained universe, separate from whatever is moving forward with this new continuity Warner Bros. plans to establish after The Flash . Considering that Ben Affleck seemed to only take the role of Batman again for The Flash after revising his parts of the script and it being a minor role compared to a cameo, it's doubtful that Affleck would want to return for a bigger, more time consuming project.