Looking for a story where loner MC doesn't go around helping others for no reason, and thinks for himself. No harems please, or any annoying girl loitering around him.
Well, Arifureta would match your MC description, but unfortunately, it's harem... "The World of Otome Games is Tough For Mobs" is also another match for the MC, but again, harem...
This fits my novel perfectly: Occidendum The novel is about a world where assassination is legal and the MC is a self-centered sociopath that loves to manipulate the people around him. He does anything necessary to achieve his goals.
While I'd definitely rec Abyss Domination and MC is indifferent anti hero besides caring for his lil sis and wife, but it's kind of harem-ish? I'm actually not too sure since I haven't finished the novel but there were a lot of love interests besides his wife at least. Though on the other hand, Sauron/Soren (name of MC) doesn't spend that much time with any of the love interests since he's always busy and his wife usually has her own things to do as well... But women I can recall off the top are Spoiler: potential love interests I can recall Mystra (technically another woman, but in DND everyone who becomes Spoiler: minor spoiler the goddess of magic is Mystra, young princess from snow kingdom (don't remember name), some dancer girl, and some automaton? in the abyss (demon world). There's even his wife's mom lol (both are high level witches)... There's probably more as well.
FFF-class trash hero Supreme magus 48 Hours a Day Nightmare's call Mystical Journey Life Mission The hunter of the apocalypse Unbreakable
I did feel like it got better but it could also just be that later on I merely enjoyed the story enough to not be bothered with such trivial things...