First R3 6* Colossus or Omega Red (both unawakened)

ClimbeRick

I'm on 6.3.3 and would mainly need whichever champ will help more with story progression. I know both will help. Really like OR, but Colossus is a beast with OR synergy. Leaning towards him a bit. Any thoughts on which champ is more relevant to my story progression are appreciated.