Despero tanked a gang pile from Superman, Captain Marvel, Wonder Woman, and Power Girl at the same time. Even at his best, how many characters on Superman/Thors level did Nefaria take at once?
As if that wasn't enough, he held up the Rock of Eternity for a bit.. It took Johnny Sorrow's attack to finally finish him off.
He took the thunderbolts, Ironman, Ms Marvel Scarlet Witche's chaos magic attacks Vision's phasing his whole body in him and a weapon specially designed to destroy him and was still laughing.
I know they are not Superman level characters but just consider the attacks... Vision's full solidification could take herald beings or at least stun them, wanda's chaos magic has worked on beings like Morgana le fay with twilight sword, blodwreith etc...adding to this a gun used by Pym specially designed to disrupt him he should be feeling something.
However Despero wins this by being more versatile, having telepathy and greater energy manipulation