The only reason I'm somewhat relieved they are most likely keeping it as Clark (even if racebent) is that if they did a Calvin Ellis or Val-Zod movie and it was a hit, I don't for a moment trust WB to not retire Clark from films indefinitely and just focus on making movies with the others. It would be the last "fuck you" to Superman. It wouldn't at all be the fault of the other characters, but I wouldn't remotely put it past this studio to find a way to make money off the name and symbol but abandon the actual main character to make life easier for themselves.
Under ideal circumstances where we had a shared film DCU (or just a Superman universe) that wasn't a mess? We'd get a Superman's own films and spin offs across his franchise and multiverse: Supergirl, Legion, Steel and Calvin Ellis. It'd be neat to see Calvin and Clark team up, Calvin getting his own movie and/or leading an ensemble cast in a Multiversity movie.