Okay, so this is an idea I've had for at least 2 years now, I had even started writing a chapter for it. But, I've decided to let someone else write this one. This happens often, I start writing something and partway through I decide I don't want to be the one to publish it. I think about the fact that if I can do it, somebody else could probably do it better. That's besides the point, however, let's just talk about how I would turn Izuku into the Man of Steel.
First off, let's talk about changes to Midoriya's origins. Specifically, we'll be discussing his paternal parentage, his father in layman's terms. I wanted this Izuku to be the Son of All Might, and with that One for All gains influence over his Quirk. I made it so when Yagi "does the deed" with Inko, OFA makes changes to the DNA of the zygote, creating a perfect vessel. And yes, I'm aware of what OFA does to those who already have Quirks, in this scenario we are ignoring that whole dying thing. So yes, this Izuku will start with his own superpower.
What's his Quirk Called? Solar Cell, which allows him to passively absorb solar radiation into his body, increasing his speed, durability, strength, and regeneration moderately. His cells can only absorb so much though, so this energy is limited. His Quirk has also affected his body, slowly causing him to grow denser bones, organs, and muscles, which will continue to increase until he reaches maturity. One major drawback of this Quirk is his fatal allergy to Red Solar Radiation, leaving him in a state similar to cardiac arrest. This Quirk also has the added benefit of giving Izuku longevity, meaning he'll both age slower and live far longer. It also makes him self-sustaining, so he'll no longer need to eat or sleep, but he does just to seem more human.
Obviously, being All Might's son and having such a useful Quirk, he'll be gaining OFA, which also has a few changes of its own. First we'll talk about how the Stockpile portion affects Solar Cell. Basically, it will allow Izuku to store far more, basically a limitless amount of Yellow Solar Radiation, as well as further increase the density of his bones, organs, and muscles, to the point of indestructibility. The Quirks inside of One for All have also changed, however. Float evolved into true Flight after spending possibly decades in OFA, allowing Midoriya unparalleled mobility in the sky. Blackwhip has been exchanged for Heat Vision, which switched to running off of solar radiation instead of body heat, it also grants the Solar Flare ability, where Izuku expels all his stored energy into a powerful blast of heat. Danger Sense has been replaced by Hyper Senses, enhancing his senses to godly levels.
Smokescreen is changed to Extra-Vision, granting X-ray and Microscopic visions. Fa Jin is now a Quirk known as Hurricane Lungs, allowing Izuku the ability to unleash powerful gusts of wind with a single breath, which can also be focused into freezing both water and Villains solid. The unknown Second User's Quirk will be exchanged for one that Midoriya uses on others, not himself. It is known as Safeguard, and it allows the user to coat anything they touch in an extremely durable barrier, which will prevent damage. The reasoning behind giving Izuku this Quirk is that Superman has a bio-electric aura which surrounds him, granting him and others protection from moving at super-speeds and preventing him from bursting through planes and other vehicles as he lifts them. It's also what gives him his supreme durability, but since Izuku's indestructibility comes from his ultra-dense everything I figured that we could explain the reason why he doesn't crush people to death on accident when going hyper-sonic speeds as a OFA Quirk. I think it works pretty well as an explanation and if we say he uses it subconsciously when protecting others it would make complete sense. "Oh but what about when he's fighting villains?" Well just say he either subconsciously doesn't use it or weakens it just enough to not let him kill but still damage enemies. Technically I want Izuku to slowly unlock the OFA Quirks over the course of the story, but there are two I think he should unlock off the bat: Hyper-Senses and Safeguard. He won't realize he already unlocked Safeguard but he will definitely notice Hyper-Senses. All the new information will cause him pain and All Might will have to help him focus
This is obviously just the original story with some extreme changes made to the protagonist, so we'll have to change the antagonists a little to compensate for Izuku's godly Quirk. So we up the strength of the USJ Nomu's Quirks making him a pseudo-Doomsday. Obviously we can't have it be exactly like him, where it would resurrect after death, becoming immune to dying that way again. But it will become far more difficult for Izuku to beat. The USJ Incident is where I think Midoriya should unlock Heat Vision, as a way to permanently destroy the Nomu. Some time during his reign, AFO should have stolen a Quirk or a few Quirks that allow him to emit various kinds radiation, which will lead to him discovering Izuku's fatal allergy during the Superman and All Might vs AFO fight. Overhaul learns of this and devises a bullet that would deliver a dose of this radiation to Izuku, thus beginning the Villains' ability to counter-attack when Superman is on patrol. Eventually, this tactic will fail because Izuku's costume will still be upgraded several times throughout the story, leading to some kind of technology to aid Izuku in quickly removing Red Solar Radiation from his body.