I got the chance to borrow a friend's S8 which has both borderless screen and curved display (that's what we call 2.5D I think ?).

Edge swipes are working great on it !

When holding the phone, my fingers tip where not above the screen (just resting on the edge, but that may depend on phone/hand size ratio), but on the opposite side, I had the base of the thumb (metacarpal part) partially covering the screen edge.
There must by some hardware or software mitigation for that, like palm detection on touchpads on laptops, because even with that, i could trigger easily edge swipes with the thumb from extreme edge of the screen.

Having the 2.5D screen in this case helps I think, as the thumb is always on the screen when triggering the edge swipe and not switching from the case to the screen, with feels a bit less comfortable.

Don't take this post as a will to have a border less screen, only a feedback that it could actually work quite good. Depending on the price and availability or your options, that kind of solution shouldn't be put away against usability issue fear.

And I too would be happy with a 1080p screen. Even the Jolla 1's resolution. Quality is more important than pixel count to me. In that regard AMOLED would be a must, but not sure it could be available...