thing is there are two incarnations of Captain atom. New 52 is basically dr Manhattan, but with a lot more feats. This is what >>83507449
is talking about. He was even show to be stronger than speedforce.
then there is the preflashpoint captain atom. He is also extremely strong physically, easily superman tier strength, durabily, speed. And he
has top energy manipulation skills and limited matter manipulation.
Major force is potentially as strong as captain, but he is not most of the time. He is not as skilled as the good captain. Thats why he cant fly. Think it like a standard green lantern and someone like Jordan. Same pontential, same powers yet Jordan is always stronger.
This captain atom has shown to be extremely strong yet he is holding back because his humanity cant accept him being a godlike being. When he got crazy he became Monarch that could end Dr Manhattan with a wave of his hand.