There's a few in that vein or similar. Specially korean mangas like https://myanimelist.net/manga/150210/After_Ten_Millennia_in_Hell

And some fantasy japanese ones where they reincarnate and are nerfed or were OP in a game world got reincarnated and the skills are nerfed, so the whole thing is more about seeing how they grow to get big again.

But I guess these ones are still in the same vein as power fantasy because it's about seeing them grow into being super OP again. So not exactly what you want I guess.