Dolphin can load the mod from a virtual SD card while reading the original Brawl ISO. Guide - Brawl to Project M For PortablizeMii - BitBuilt
Development officially ended in 2015, but the mod remains hugely popular in the competitive Smash community. super smash bros brawl iso for project m top
Even with a good ISO, you might hit snags. Dolphin can load the mod from a virtual