Since I'm only including MCU heroes currently on Earth as of the end of WandaVision, this leaves out Thor, Monica Rambeau and Captain Marvel. While not a hero, for the sake of this rumble, Abomination get pardoned to battle Brandon.
Who dies or is severely injured fighting Brandon 1-on-1?:
Who stomps him?
Prof. Hulk
Doctor Strange
White Vision
Scarlet Witch
Valkyrie
War Machine
*Abomination