That's gonna vary DRASTICALLY depending on what your players want out of the system. Have you looked at generic toolkit systems (Fate, Savage Worlds, GURPS, Genesys), or do you want a system focused on providing a low-magic fantasy feel? Does it need to be a d20 system, or is your group open to exploring other dice systems?
If they just want a low magic game on the D&D 5E chassis, look at Adventures in Middle Earth. Obviously, it's themed for a specific setting, but the fluff is easy enough to shift to your tastes, and the mechanics are good. Ironsworn is a good (and free!) game with strong PbtA (powered by the apocalypse) influences, but is strongly themed towards being adventurers who take on quests, which might not be what you're looking for.
Those are just the ones I have personal experience with. I know there's at least one Conan RPG, and probably dozens of other RPGs aimed at low-magic gaming that I haven't played or heard of.