Well, I agree about the human part, but the fighter part? Not so much.
Aaragorn is totally a paladin. Or a ranger, depending on your view. Gimli, Sam and Merry might be fighters, but Frodo and Sam are not. Bilbo is a rogue.
Conan the Barbarian. Its right in the name.
Robin Hood is totally a Ranger.
Wu Xia stories default to the monk class.
You've got Eragon with the mix of magic and swordmanship, but the magic comes from the oath to the dragon, so paladin to me once again over Eldritch Knight.
King Arthur is pretty much an iconic paladin as well.
D&D novels tend to have wizards and rangers and rogues and clerics as main characters. Kelemvor is about the only actual fighter that I'm aware of, and there were a ton of characters in that story arc.
Heracles is totally a barbarian.
I know of a few stories with tactician / warlord types, and that's supposed to be part of the fighter chasis in 5e... but that's not the intent I think you're going with here.
D&D's version of the Ranger and Paladin rely greatly on their sorcery/supernatural abilities. I don't think anyone wanting to make an Aragon, Robin Hood, and King Aurthur character is particularly keen on their supernatural power- and definitely not in the form of charms and spells ala Gandalf or Morgan la Fay.
I'm also challenging the idea of modeling Hercules as a Barbarian as his going crazy and murdering his family was very
out of character for him. He spent the entire rest of his story trying to atone for it. I'd hardly use a class that reliably flies into a murderous rage nearly every day to represent him.
So, who are these legendary Fighter types? Most of the ones I can think of actually fit other classes better than Fighters. The only real exception I can think of is the main character stories of some MMOs seems to default to a fighter/warlord mix type.
Aside from the ones already mentioned, most western fantasy readers/players are also familiar with Gilgamesh/Enkidu, Persus, Achilles, Odysseus, Finn McCool, Baldur, Beowulf, Samson, Link, John Snow/Brienne of Tarth/the Hound/the Mountain/Gray Worm etc.
And before we get into the, "but they had divine aid/demigod blood so they should be Paladins/Clerics..." argument, we should note that this is the case for most everyone in old tales.
Merlin and Morgan la Fay were of supernatural heritage. As was Circe in Greek myth. Sorcerers in the Hyborian age get their powers from bargains with dark powers and become inhuman in the process. Magic and sorcery in nearly all cases was the work of supernatural beings in one form or another. And of course there's good ol' Gandalf- the poster child for what in D&D is a human secular arcane wizard- who was actually a nigh immortal spirit sent by a more powerful spirit of goodness and just happened to be in human form, but could have fallen to become a firery horned fiend- aka an angel. If you really want to get pedantic about it, Tiefling/Aasimar Sorcerers and Warlocks (and to a lesser extent, Clerics) are much better representations of most any well known spellcaster than D&D's Wizards are (save Harry Potter et al).