The hurdle to jump over is accepting turn order as "simulation" of character reflexes and speed. I don't personally find it it to be a big think to ask.
This is indeed what it comes down to. And it goes to the debate going on here about "pausing" in RTwP versus TB combat. Yes pausing is present in both systems. But actors acting by taking turns is present only in one. It is not the pausing that is immersion-breaking or unrealistic in either system. Pausing is merely the temporary stopping of time to help facilitate your actions. It is the turn-taking that is the problem. Actors acting in turns, and that too in turns during combat of all things, is the problem. I can never accept combat at the tactical/individual person level happening in turns as being a realistic simulation of anything. It is the turn-taking that I describe as unrealistic and fake, and then by extension immersion-breaking.