Dan is the man for this. Probably the highest quality option that seems realistic - though I’d still prefer Gunn dramatically reduce his involvement and just let Dan do his thing if that’s the case. Or wait til the next reboot and give him a shot when he could actually have control.
Not that Dan is a crazy auteur or anything, he’d crush a pre-existing script, but idk feel like he’d make a super fun pulpy Batman movie with his own narrative instincts.