I know another guy who does Naruto fanfic (cross and non-cross) and he's one of the few who does great work at a novel level with that fandom and no bashing and other nonsense, but the guy doesn't stop making new work and almost quit aside from the old ones (maybe an annual update with luck), he literally has more than 200 fanfics, almost all of them with more than 100k, to give you an idea of how much he writes, of the lengths he will have finished less than 10, he has arrived to the point that I don't even read it anymore unless it's finished and look, I'm very tempted, but I refuse to be in plot limbo for so long. I understand the need to change jobs to freshen up, but in my opinion there is a limit to how much you can do that until people get tired of it and the name only serves to warn you to read only when it is finished.

The protagonist may not have anything with the navy but maybe Gate: Jieitai Kano Chi nite, Kaku Tatakaeri could work since in essence the whole thing is like in the navy but from another perspective.

I like that you have put G-8 in the manga, one piece as a rule has good fillers but this is one of my favorites

The queen of the world thinks the same as me, this enel arc has been the least interesting out of the anime fillers, it's not that it's bad, Oda can't make bad arcs, just something boring I liked the ending, the noland thing and the above to go up to the island but the rest was tedious, for me it is the worst arc in general, I'm talking about the manga by the way not fic fic.