Some comments.
I don’t generally write screenplays. I looked at the format, and I understand it, kind of (since I don’t write them, I’m not really familiar with it).
But the biggest issue I see with the two samples you showed is this:
Across Scrivener, the ruler is not accurate.
On-screen in Scrivener, Courier 10-point looks to be about 9 characters per “inch” (54 characters in 6 “inches”). It should be 12 per inch. And Courier 12-point runs perhaps 7 (44 characters in 6 “inches”). It should be 10 per inch. The ruler is wrong. Period. And the amount that it’s off changes with zoom level.
This is why the width doesn’t look right on the screen; it ISN’T. If you use 10-point type, it’ll look okay on screen, but you can’t send them 10-point Screenplays; you’ll look like an idiot.
Screenshot sections –
This is Scrivener’s ruler, supposedly 6", versus Courier 12 point type. Note, I can get 43 characters in there. Should be 60.
Here is what the output looks like, in Adobe DC reader, with a measurement of the width in red:

43 characters =~4.27 inches. That’s about right.
Until the ruler is fixed, you cannot get them to look right on screen, unless you pull some tricks on it (and you shouldn’t have to, I know).
Possibility 1: If you use 10-point type, it’ll look right (or close, anyway). But you’ll want to override the font in Compile to use 12-point Courier Prime or Courier New, if you do that.
Possibility 2: Stretch the ruler. Remember, 6" in Scrivener equals 4.3" or so. So move it out to 8.3", and 60 characters of Courier 12 will fit. But your tabs need to be adjusted, too, because they’re wrong, unless you fix it in Compile.
*** Technical bits. I think the reason the ruler is off is because the ticks on it are eighth-inch ticks, and Scrivener uses 6 of them per “inch”. So 36 ticks should be 6 inches were they 1/6 inch ticks, but… those ticks are 1/8, not 1/6, so 36 of them only amount to 4.5", instead of 6. I could be wrong, but the numbers are close enough to draw me to think this.
*** This may be addressable by scaling the ruler to correspond.