SV Superman wins, and it's not even remotely close.
After "billions upon billions of years" of training, Superman's powers evolved to such an extent that:
-He created thousandS of duplicates/avatars(ie. "Super-Sentries"
to help him be in multiple places across the universe at once.
-Just one of these duplicates(ie. a fraction of his cumulative power) was able to hold together the universal core for "countless years", thereby preventing the universe itself from collapsing.
-He could casually access higher dimensional planes(beyond even the 5th dimension) -- dimensions that gave even Mxy himself pause.
-He could bridge various points in space-time, just by physically pulling apart reality itself.
-He outraced the nigh-instant entropy-death of the universe.
-He survived a big bang, and swore to protect the next universe.
-etc. etc. etc.
He is the most powerful version of Superman that has ever existed, imo.
