There are various videos online of people doing things that I would consider physically impossible. Heck, just watch an old Jackie Chan movie where he's doing all of his own stunts. Have you ever seen what Simone Biles the gymnast can do? It looks like she defies physics, it's pretty amazing. On the other hand I don't expect D&D to be particularly realistic. They shoot for action movie logic unless magic is involved. As far as how much you can do in 6 seconds, I just explain that 6 seconds is an average and not to get too concerned about pulling out a stopwatch. YMMV of course.
What I don't want is Celtic, Greek demigod, or Paul Bunyan mythic. It's just never been the imagery supported by D&D, with the exception to a degree with 4E. I don't want to play Anime the TTRPG, I want to play D&D,