Black Adam was, for many years, a pretty generic "counter" villain to Cap Marvel in the same way Reverse Flash, Sinestro, or Bizarro were to their respective enemies. I think he first got fleshed out as a complicated "anti-hero" by Geoff Johns during his time writing JSA in the early 2000s, when they explored his backstory and motives, and how he's sort of like a Ra's al Ghul, who is willing to kill for the greater good (of protecting innocents in the case of Adam). I've read several of those TPBs and they are pretty good as far as modern DC goes.