No problem at all. I recall him beating her, thing is she didnt lasted long as godess under Byrne. Was she actually still one when they fought?
"the basis lies in the similarities in their cellular structure"
I just dont see how can we be sure they are the same. Odin having natural magical protections against several attacks unlike Darkseid its another point. He has so many options avaiable.
"galactus because his physiology is completely different to anything else in the universe."
Hes a humanoid being that sprang from the late Universe. He was mortal at first. So i dont know...it shouldnt be different. Or that much. Odin also looks humanoid but he isent Human. Problem is Snake thats too much of a inconsistant way to beat someone when we only saw a Darkseid that doesnt manage to be Top dog go down. And it was designed for him. They would have to know what Odin is and how his system works before they do it. And its different than Dseid.
If for example they did it to lets say Zeus whos like Odin...then you would have a solid point.