In the 1980s, one of the greatest works of science fiction ever to come out of Japan first hit the shelves as a light novel: Legend of the Galactic Heroes. It would later get adapted into a 110-episode anime series, produce two movies, and several side-stories mini-series. Unfortunately, only recently did the original light novels get licensed for release into the West. (You can fix that here)
Whether you read the novels or watch the anime, you’ll find a truly epic Space Opera that hits most of the things you want out of a Superversive work. While the moral clarity is muddled at times, as this story reflects the mood of its day, the protagonist and the deuteragonist (and their key allies) are clear heroes with heroic virtue and epic flaws.
There are no supernatural powers. There are no aliens. There are no giant robots, laser swords (save for those shown as part of an in-fiction feature film), transformable machines, or other tropes popular with the famous SF/F franchises arising in Japan at this time. The fantastic elements are confined to FTL travel, cybernetics, the many technologies implied by the fact that galaxy-wide human colonization occurred, and high-end medical technologies. Yet there are massive fleet battles only eclipsed by E.E. “Doc” Smith’s Lensman series, and cultural conflicts (with attendant political intrigues) that drive the plot overall (and thus many subplots therein).
What there is, however, is true love (but often filial instead of romantic). What there is, however, is courage against often ridiculous odds. Faith held against powers willing and able to destroy you and yours, and fortitude in times of struggle are what you will find here. And, while individuals can succumb to their tragic flaws, the overall conclusion is hopeful in both absolute and practical terms. If you can find a good playlist online, and you can deal with subtitles, the long-running series and its related works will bring you up without lying to you on what it often takes to climb that mountain to a better tomorrow.
Moreso than any other work of science fiction or fantasy out of Japan, I recommend Legend of the Galactic Heroes, especially if you like your key characters to be competent as well as their opposition. Victory here is earned, and therefore deserved- including the hopeful end.