Wouldn't make any sense for him. He's very hands on as a producer-director type and thus is used to having almost 100% control of every aspect of film development. Someone said it could be political, to play hardball WB, but why go to someplace that would handcuff you...rather than Paramount or Universal?
Honestly, I think he'll see the Snyder cut success, as an avenue to get more leverage...since he was always against the Whedon cut, and it could give him a different place to explore his creativity. That and WB will probably be desperate to keep both him and Denis in their stable, so there's probably no need for hardball play. They both talked mess openly, because they know WB will bend for them. If they leave, WB will have trouble courting other talent.