Atum is immensely powerful; he is believed to be more powerful than any other known god on Earth. Atum emanates light and heat as bright as the sun as blasts and while flying.
Atum possesses god-like abilities, the full extent remains to be revealed. He can generate light, heat, and plasma on levels par with Earth's sun, and can survive even in the heart of the sun or in deep space. He can fly at faster-than-light speeds.
Atum is able to absorb the essences, powers, and abilities of others, even other gods and abstract entities. When doing so, Atum undergoes a physical transformation into Demogorge, with wings, grey skin, and increased power. As Demogorge casts off excess power gained in this manner, he gradually transforms back into his original form.
is atum capable of absorbing beings like galactus?
Atum the God-Eater/ Demogorge will smite them like he did before, the old elder gods devolve into demons and left into pocket universe to escape Atum wraths including Set, Cthon, Cyttorak etc. Demogorge form is unbeatable it will aborb beings to make it more powerful than before, he can absorb all of the sky fathers on earth and kick Dormmonu, Mepshisto ass out of their own realm.