Honk Kong was given back to China over the objection of its people because it belonged to China. Ulster is a province of Ireland under foreigh rule. There will be no peace until Britain gets to Hell out. They are the source of the problem so can never be part of the solution.
If Hitler had conquered Britain in WW2 and populated London with enough German citizens to have a majority , then gerrymandered the boundary and said the city proper would remain part of Germany even though he would withdraw from the rest of the country, would Englishmen accept that as the wishes of Londoners? The way that Ireland has been treated throughout history would shame all the devils in Hell!