Something to remember about Captain America, as a high-level martial, is that he's a lot more than just "peak human". A peak human is... peak at one thing, because there are tradeoffs, physiological compromises that must be made. He is not just as strong as Hafthor Bjornsson and as fast as Usain Bolt and as nimble as Mary Lou Renner-- he is all of these things simultaneously with the perception and instincts and split-second conscious decision-making capacity to use all of these capacities in conjunction.
He's not just a double-digit Fighter/Rogue/Monk with straight 24s. He'd demolish a D&D campaign and he's the Designated Mere Mortal in his franchise.
I really... don't want high-level Martials in D&D to be like Hulk and Thor. I want the archetypical high-level pure martial to be Captain America, with the choice of being Iron Fist or Psylocke instead being a real tradeoff.