This is such a bad implementation.
A) Snap to pixel alignment isn't working for me, I don't know why, I assume something else in the snapping is overriding it. I have spent the day rounding off numbers, and then accidentally one board that was imperceptibly an extra pixel wide.
B) Even if it was working, all we really want it to not have to think about this and the sheer volume of people talking about this issue shows that it just doesn't work.
I have just moved over and used designer all week so it's crazy that of the hundreds of features I have used this is the thing that is making me want to move back. I guarantee you that most people working in the software want a grid of artboards and not to have to think about if they will export at 1081px or 1921px. They don't want to toggle a (finicky) setting on and off just to duplicate boards, I have literally never wanted to have one artboard placed 0.1px below the other in 20 years of doing this, just make artboards snap to pixel by default.