The MC could save the fantasy world from a demon king and on Earth he could introduce the cure for all forms of cancer, but he would still keep thinking he's the most miserable person to ever exist and not worth anything. If there was a measuring device for self-pity, it would show over 9000 if pointed at Yuuya.
I wish this terrible trainwreck of a series had kept the MC's original ugly looks, even if he had otherwise got stronger with the cheats. It would have been actually interesting, with the people he had saved wanting to express their gratitude, but at the same time likely not be at all enamored with him. If the princess in her shock hadn't seen him properly and only formed the image of a dashing prince in her mind, but the reality would have been a short, obese, ugly emo dude, would she have proposed immediately? I think not. She would have still surely thanked him and perhaps offered some rewards, even invited him to visit the castle, but that's probably the limit. In the new school, he wouldn't have immediately made friends, either. He would have likely been cordially ignored.
It would have been so much more interesting, plus it would have actually made it more realistic the dude still has no sense of self-worth.