A familiarization question really- What does the 12-bits cover? IOW, how much of that is beyond the screen upper and lower boundaries? What's the expected number of vertical steps over just the screen?
That is easy to establish.
There are measurements Max and Min.
If you enable them and set scope to clip input signal, it will show max measured value.
For instance, at 1V/div, (±4V on screen) it will show +4,258...V Max, and -4,26...V Min.
So roughly, you have a quarter of a DIV above and below the top and bottom edges of the screen.
So if you single shot a 8.4Vpp signal at 1V/div, and change to 2V/div, you will see full signal.
Over that, it will clip.