The war with the All for One ended and Izuku was allowed to rest, using the remaining energy of the One For All to save some more people, finish school and then move over to another profession that allowed him to help people, while enjoying the fame of being at the forefront of saving the world. And thus ends his story.

....

Yeah, right. No way it would be so easy. Instead of enjoying his early retirement from the peak of heroics, he ends up waking up as some sort of biomechanical facsimile of a person in the distant future. And it's not even the distant future of his own world, but of some sort of alternative timeline? And in space? With his first acquaintance in this foreign world being a psychopathic AI who considers AM and Skynet to be their role models?

So much about retirement.