NI have the best of both worlds , what's the problem , unfettered access to us and the EU .Exactly the point. There IS a settlement. It’s called the Good Friday Agreement. It details how NI constitutional status can be changed in the future, or not as the case may be, through a border poll. It has also effectively negated the border with the ROI as a permanent pain in the ass for all those who live there.
It has brought decades if peace and stability. There can never again be a hard border there.