>>4351354Aperture wont change your focus point, but it can change what is or is not in focus. Focus is the actual point of focus. Aperture affects how far in front and behind that point is also in focus, and how rapid the transition is to out of focus. Like the focus plane is a sheet of paper, and aperture can affect how thick that stack of paper is.
Some lenses exhibit "focus shift" where the actual plane of focus can shift slightly as aperture is changed. Some lenses also exhibit field curvature, where plane of focus can curve at the edge, and this can also change as aperture changes. Both of these are lens specific faults and ideally shouldn't and don't occur in nicer lenses.
Depending on the width of the lens, distance of landscape, field curvature, etc, you could shoot landscapes at f1.2 It really depends on the lens.
At f1.2 you would need your subject on the same relative plane of focus as the background. You could play into a lens with high field curvature. An actual tilt lens will let you do it, they work by tilting the plane of focus.
