A Young Justice and Steven Universe Fusion AU!
On the premise of what-if Greg was left on the doorstep of a childless couple of a Smallville farm, aka the Kents get a surprise before Clark even comes into their lives.
Clark gets an older brother! Greg’s younger brother becomes Superman! Because of his much happier and healthier upbringing, Rose and Greg become even closer, and unlike in SU canon, Rose tells him who she used to be. With a much healthier mind-set when the two of them decide to have kids, and using Kryptonian tech Rose doesn’t have to die to have Steven!
By Independence Day, Superman already knows what it’s like to have a brother, and a ten year old Steven is his sidekick. By that point there’s already a lot of butterflies utterly destroying canon.