Classic Beyonder (Secret Wars II) vs The One Above All (in a well-functioning multiverse)
Who wins?
STO
StoicAvenger
TOAA and it isn't close.
AST
AstnerThe Ghost Who Walks
Thanos after having absorbed all the Abstracts in the multiverse was able to overthrow the One Above All. The Beyonder was millions of times greater than the rest of the multiverse combined, and that was with the Molecule Man in the equation.