Why not have Burton direct Batman 3 and Superman Lives as DC Elseworlds?
Burton directs both back to back. budget 100m each. Release in the 'Elseworlds' division of DC Universe (alongside The Batman, Joker). Ideally theatre only release but could do limited theatre/streaming if necessary
I get they wouldn't want to do that with DCEU (releasing Synder JL2, MoS2, the Batfleck movie as Elseworlds movies) as its the previous recent regime that Gunn trying to distance from, but a Burton Batman 3 & Superman Lives would be ideal in DCE
Batman 3 would star Keaton (obviously) and probably be based on Batman Beyond/Dark Knight Returns.with Michelle Pfeiffer returning as Catwoman and some older villains cameos (had Keaton/Burton done more back in the 90s) like Riddler (Carrey as no Williams), Dr Freeze (Patrick Stewart), Poison Ivy (Demi Moore?) and Batgirl (Winona Ryder), plus Cage Superman maybe (Keaton could cameo in Superman Lives) and maybe the big villain he'd go up against could be either the son or a copycat of Jack Nicolson's Joker (Depp)
Superman Lives would star Cage (minus CGI!) with the cast that would've been it in 98: Sandra Bullock/Lois, Chris Walken/Brainiac, Kevin Spacey/Lex,