The amount of dead time is a major reason why I stopped umpiring baseball. It was no longer fun to work games where I would stand around for long periods of time in either A (traditional mechanics, no one on base), or the B/C positions (runners on base, or no one on in modified COVID-19 mechanics) waiting for the ball to be put in play. Unless I was working older age groups (16U+), most stolen base attempts were non-competitive, so I really didn't have much to do as the 1st base umpire. It's marginally better calling balls and strikes from behind the plate, because I need to pay attention to the game for my own safety, but having to call balls on many consecutive pitches, some of which just barely miss the strike zone, wears on everyone. It's a pity that many things that you learn in training class (how to rotate as the plate umpire, stolen base mechanics, following the runner to 1B as the plate umpire) are rarely useful, because many situations don't happen very often.