This may be a bug in the software, or maybe it was how it was designed (which is terrible btw), but I’ve noticed when I am watching my camera via playback and I zoom in to see something, the controls disappear as you zoom in. You lose all ability to pause, capture an image, etc when you are zoomed in. Its not until you zoom all the way back out that the controls reappear. Am I missing something here or is that correct? Also, how the hell do you skip ahead or back like 30 seconds at a time instead of dragging the bar?
You did not say if you were on Android or iOS, and you did not tell us if you are trying to use portrait or landscape display. In portrait, you are right that if you zoom in far enough, the controls disappear. In Landscape, the controls will come and go when you tap on the screen (regardless of zoom). Note that the image display is FAR larger when in landscape mode.
As for time, the slider is it, HOWEVER, if you are not aware of it, you can change the scale with a pinch in or pinch out on the time slider. Fully pinched in, allows moving hours at a time, and fully pinched out allows selecting time within a few seconds.