Ok, I don't seem to be communicating very well, so, let's give an example (that will likely get picked apart to death, but, hope springs eternal.)
Here is a standard turn for a high level monk/fighter (the character I'm playing). I'll skip the actual die rolls because they don't really matter, just the results.
Monk: I start my turn with a flurry and attack Monster 1. I hit? Ok, make that a Stunning strike. He saves? Ok, make that a push attack? He fails? Ok, he moves back 15 feet. Great. I move over to Monster 2, second flurry attack hits, let's knock him prone? Success? Ok, next attack, hits? Ok, let's take away his opportunity attacks for this round. I now Step of the Wind (automatic because I spent a Ki point) and pick up the fighter, moving him back to the first monster. I take a nick attack on Monster 1. Crit! Yay. Hrm. I move half my movement from the crit (25 feet) over to the base of the wall. I then move up the wall (high level monk) to the balcony to post up where Monster 3 has been sniping at us. Two regular attacks. Hrm... it's almost dead. I'll Action Surge and take two more attacks. First attack hits, damage. Second attack ... Crit! Yay advantage and halfling reroll turning that 1 into a 19 (fighter levels FTW). That finishes off Monster 3. Ok, I step off the balcony, slow fall to the floor, and use my remaining Crit movement to move back to Monster 2.
That's a pretty bog standard turn for my monk. The die rolls are NOT the problem. I don't know how many times I have to repeat that. The die rolls are NOT the problem. The problem is, even with pre-rolling all the dice, that turn would still be that long. Two of those movements I could not have planned for. The Action Surge could not have been planned for since I wouldn't know that I would be able to attack Monster 3.
Since you don't actually have any experience with VTT's, perhaps it might be more useful to take me at my work when I say pre-rolling IS NOT THE PROBLEM.
How is, "I want to streamline the system so that characters and monsters have fewer actions per turn that require sequential resolution" not a suggestion? It's a suggestion I've REPEATEDLY made over and over again. And the response I get is, "Well, you should pre-roll your dice."
This is why I say you aren't actually listening.