Garen is losing because he's a dirtbag in the God King lore
Think about it.
Guy kills his own men without remorse and have his soldiers fight for him before fighting. He stands behind them and watches them die.
Darius leads his own army like a badass and doesn't see himself above them. He has a brotherhood.
Garen says "Our faith protects us. I am our faith". Arrogance that exceeds that of Darius'.
Of course people are going to pick Darius. Why would you pick a God-king with a holier than thou attitude 24/7?
