It's kinda the point of the character, though. He's this lumbering force of nature with a very black and white view of the world. He's intentionally written as a Gary Stu; but funnily enough, he's not as blatantly overpowered and covered in plot armor as Rey from the sequel trilogy.
I sort of beg to differ. He’s unstoppable to the point of having magic power in a “realistic” universe. Rey is just a particularly quick learning wizard in a universe that has wizards.