I am not gaming in Conan's Hyborian Age in an effort to not allow the player characters to be overshadowed and to allow more freedom. I kind of like it when a setting also includes cultures like Atlanteans, Hyperboreans, Lemurians, even the Kimmerians from AS&SH (similar to Conan's Cimmerians) that seem to be from a pre-dawned earth age.
Which would be your choice for rules and setting between the ones I haver it narrowed down to?
Beasts & Barbarians Steel Edition (Savage Worlds)
Astonishing Swordsmen & Sorcerers of Hyperborea 2nd Edition
Crypts & Things Remastered Edition
Barbarians of Lemuria Mythic Edition
Atlantis the Second Age
Setting - again I cannot recommend Primeval Thule strongly enough. It is a coherent and very well designed setting that does exactly what you want. You can likely pick up a print copy for eg 13th Age cheaply and use for your preferred system, though I love the 5e D&D version.
Rules set - this is about what you want out of the rules, and I'm not familiar with all of these. All D&D derivatives will tend towards an everyman-to-superhero feel, which I like, it is very gamable and lets you start small and low key, then see the game build over months or years to earth-shattering conflict in a now very well developed setting. Of the listed systems I like Crypts & Things, which is basically OD&D, best.
Re Barbarians of Lemuria, in the edition I have armour is damage reduction, and the more bits of piecemeal armour you have, the more you reduce damage! This is very poor design IMO and doesn't give me much confidence in the system. I also dislike Savage Worlds combat, especially the bennies, but for non combat task resolution SW works very well. I have no idea about Atlantis the Second Age.
If I were not going to use a D&D based game for S&S, I'd probably go for a WEG-d6 system like Mini-6 or maybe d6 Fantasy for an heroic tone. Or for low powered horror a BRP d% system like Runequest 2e and Call of Cthulu. Runequest/Stormbringer PCs vs CoC Great Old Ones would be fun. Nasty brutal & short, but fun.