Curate, connect, and discover
Danny running away from his home dimension for such and such reasons (GIW, bad reveal, etc, etc) cue him stumbling around Gotham because holy mother of ambient ectoplasm, Batman.
So anyways he’s just chilling in crime alley, as a struggling guy in Gotham does and then. And then there’s someone else. Looks exactly like him. Not like how he and Dani look similar, her features just softer and rounded with babyfat, no, no, this guy looks exactly like him. Down to the barely there scattering of freckles on the nose bridge.
It’s Jason Todd. Danny is his dimensions version of Jason Todd.