I can't speak to Beowulf, but if you take the Pen Fight from Bourne Identity, the following actions occur which have no D&D equivalent:
- Grapples a weapon / limb to prevent the use of that weapon
- Damages the opponent while disarming them
- Puts the opponent into a chokehold, depriving them of oxygen
- Escapes a grapple by damaging the grappling creature
- Uses positional leverage to gain an advantage on opposed checks
- Shoves and damages the opponent with the same attack
- Attacks when an opponent enters their reach with an unarmed strike
- Targets and disables a specific body part, preventing weapons from being wielded by it (or later, from it being used to walk)
- Knocks someone over furniture for additional damage
- Incapacitates a target via damage without having them restrained, unconscious, or dead
^All of the above is not present in D&D without DM adjudication or houserules, and that's a 90 second scene depicting a (from my understanding) fairly realistic fight between the real life equivalent of high level fighters. It's not some crazy anime kung fu stuff, it's just real stuff we as humans can do, which cannot currently be done in D&D by a 20th level fighter.