With a week of prep this would be narrowed down to Thanos, Darkseid, and Apocalypse. (all have genius intellect.)
Doomsday and Juggernaut are relatively dumb compared to the other three, so with a week of prep they would be eliminated from the battle. Darkseid would then be the 3rd to be eliminated and it will be a showdown between Thanos and Apocalypse. From there, I think Thanos would win that battle.