So I am very interested in seeing, what the champs manage to get out of it
Me too.
I underestimated the power of sacrifice and the frequency of enslavement achievable. Each new capture cut off six turns from my projected end date making it difficult to know how long the slaves should road for later slaves before they trotted off to be beheaded in the capital. Lost a few turns there. More could perhaps be won by selecting another strategy.
My strategy was to build Sacrifical Altar (3750 BC) and Temple (3300 BC) as fast as possible, a Pottery, a Settler Factory, an Inner Ring of cities, a Library (1450 BC), then Bowmen. As I appeared to have Bowmen enough, I also built The Statue of Zeus, but it produced less culture than a single sacrifice and only one Ancient Cavalry.
Other cities built Warrior, Worker, Barracks, Bowmen; later ones no Worker or Barracks.
Research went Pottery, then Alphabet, Writing, Philosophy with Literature as Bonus and Library in Babylon on the same turn over The Big Picture.
As soon as I had a sizeable army I attacked the weak western tribes: Russia, Mongolia, Spain. In hindsight I moved too late. Had a few turns left on the Golden Age as it all ended, so the warring part wasn't fully exploited.
590 BC, 2000 in capital. More than half came from buildings, the rest from sacrificed Slaves.