While Superman takes point of the trinity in this issue, this debut focuses much more on Harley and Booster, but there are two notable bits regarding him: one, along with being programmed by Batman with Wonder Woman's compassion, it's mentioned the Sanctuary androids have Superman's honor. Additionally - and I feel like this isn't really much of a spoiler, but it's a character moment that feels loaded enough I'll bracket it anyway - spoilers:end of spoilers Also, for whatever it's worth, King's Superman doesn't seem to have a super-memory.
Superman says that Sanctuary was built so 'they' would have a place to go to, before sharply correcting himself 'we'. Curious whether that means he isn't suffering in quite the same way as the others but is trying to force himself into that bit of human association and empathy, or, I expect more likely, he's in denial about his own issues but consciously or unconsciously keeping up a front. Interesting and very on-point articulation there of a bit of Superman's psychology, he's admitting to a vulnerability without even realizing he means it.