Byrne's run on . . . Action Comics, I think? Nearish the end of his run, he had Superman travel to a pocket universe created by the Time Trapper so the Legion of Superheroes could still have been inspired by Superboy, because the real Superman never was a Superboy . . .
Anyway . . . this Superboy still had the Silver Age level stength, speed, etc., and so was quite capable of wiping his ass with the real Superman without much effort. In the end, Pocket Universe General Zod killed everyone in the pocket universe and Superman then executed Zod and his lackeys (always two there are) for his crimes in an example of 80s-era grittiness and the biggest difference between Silver/Bronze Supes and the post COIE Supes.
Which eventually led to Gangbuster and Superman have psychotic episodes, that sent him into self-imposed exile . . . which never had any effect on anything ever again, and we should just stop talking about it.