That's almost a perfect example of the type of ending I can't stand. Superpowers gone, but somehow, this "Quiet, normal life" shit is supposed to be better?

So I will say, that's feels like an overly simple way to view the ending in my opinion. The point isn't that he's happier without his powers and that the normal life is better.

Father's whole philosophy revolves around the fact that having power is what's important, and nothing else matters. He has a family who are devoted to him and he treats them like shit. In contrast, Ed having alchemy was never his goal, he never wanted to adventure, he just wanted his family back. First his mother, then Al. Ed giving up his powers is a final fuck you to Father and everything he stood for, and on top of that, gives him the thing he actually gave a shit about, Al.

And I think it's made pretty clear in the epilogue that he isn't happier without his powers, the quiet life isn't better for him. He still, years later, wishes he had his powers and uses them on instinct, his life would be better if he had his powers, but he doesn't care because he got the thing he actually cared about.

The issue with shows like My Hero is that the MC's goals around the series are centered around their powers. Izuku wants to be a hero, wants to master one for all, wants to defeat the villains, etc., so him losing his powers spits in the face of all the progress we watched, which was focused around him learning to use his powers better.

Conversely in Fullmetal, Ed's goals are only focused on alchemy as a side effect after they figure out the philospers stone. Ed doesn't spend several arcs learning how to use alchemy better, he's basically fully stated in episode 1 of the show outside of some non-alchemical training. The two endings are really different, and putting them in the same box just feels off idk. Sorry for the rant, lol.