Fan Casting Superman: Man of Tomorrow (DCU)

I can't find what comics this movie is based on, I think it's the comic by Robert Venditti. but there is an animated movie on HBO Max if you want to watch it. If you don't want it spoiled go and watch it then come back. I still stand by my other superman movie idea for the DCU but this one is a more realistic pick for James Gunn. I mean Superman, Lobo, Martian Manhunter, it really has it all, and i think it would be best to put Manhunter in a movie before a Justice League movie without giving him his own movie.