People who don't want a solution will not find any solution acceptable
Absolutely correct.
This whole border issue is a "problem" invented by The EU to make negotiations more difficult.
Nobody wants a hard border between NI and The ROI.
So don't have one!
Put it in The Irish Sea.
For control of people, it is already necessary to show current id if you fly from London to Birmingham.
Raise id to passport and that will not inconvenience people.
Extend that to ferries too and again, no major inconvenience.
Just police it well.
That is the illegal immigrant problem sorted.
As for goods,unless the EU behave in a terribly beligerent manner, there will be few tarifs imposed.
Even then, The UK can either not impose tarifs going the other way or if they do impose them, it will be a tiny proportion of ROI goods imported into The UK.Again, causing minimum desruption.
Even then, most of the paperwork can be done, as it is now, before the goods reach the border.
A no deal Brexit will hurt The ROI much more than it will hurt The UK.
Nobody wants that.
If a hard border is imposed between NI and The ROI, it will not be The UK imposing it.
It will be The ROI doing it at the bequest of Brussels..... and at that point, Dublin will see sense.
As I have described above, there are simple solutions to this supposed problem, only staunch remainers want to ignore them.