the real world equivalent to your fighter is someone like Usain Bolt, if he had trained for melee combat rather than dashing a short distance
Ok. Let's take this hypothetical guy..this Usain Bolt of melee combat. Maybe peak Anderson Silva with a sword..Muhammad Ali in plate mail or something.
And let's move that guy into a D&D context.
Does that guy..Muhammad Ali/Anderson Silva equivalent fight D&D monsters the way D&D fighters fight D&D monsters (e.g. Dragons and Giants)..toe to toe slugging it out until one of them goes down?
I submit that they would not.
This is one of those weird narrative disconnects that comes up often in these discussions, where folks point to the John Rambos, McClanes, and Wicks of action fiction as their target level of capability without reflecting on how poorly that fiction jives with how D&D runs.
D&D melee martials don't get suitcases full of C-4, rocket launchers, and effortless headshots. They will not generally smear mud all over themselves to hide their body heat, creep quietly in the bushes covered in grease paint, or nervously army crawl through ventilation ductwork. They are not setting elaborate improvised booby traps using tripwires, sharpened sticks, and bushels of hand grenades. They are not waiting to engage in melee combat until the beast is trapped or weakened.
Instead they see tractor trailer sized creatures at the height of their powers and say to themselves "I'm gona go in and f...mess that thing up with just this sharpened and/or heavy hunk of metal"
How it's possible to think..Usain Bolt..but with knives or something is beyond me.