I've never had any beef with the Matt Bomer fancasting for Supes, for the record. I do think he's officially aged out of contention, but I think once upon a time he could've been a great Supes. He's a great actor with an inherently warm/kind presence, which is the main prerequisite any Superman actor needs for me before we get into any other qualifications, imo.
And yes, Indigo, Brainiac 8, is female, but I've no interest in seeing Indigo adapted when we haven't seen OG Brainiac properly adapted for the big screen yet. I'd be fine with a female cast as the main Brainiac as well, though I think there are plenty of great male or female candidates for that one.