I wouldn't blame you at all for jumping on a plane.
The banks are greatly to blame for this present mess -and they are supposed to be the experts, not the hundreds of thousands of property purchasers,especially young people, in dire straits.
In USA you'd have no problem in telling the banks that recklessly threw money at people that you can't pay -here are the keys. It is recognised there that banks must share the risks with the purchaser.
I'm not an expert on how banks chase people for debts. If there is some sort of border watch I'd be amazed. I'm not that sure that you'd have any real problem if you came back to Ireland in a year or ten years, except if you considered ever applying for a loan or bank account etc.
But you'll always have some anxiety even if it is unfounded. Thus it would be better if you found out what is the worst that could happen if you openly and honestly declared that you just cannot pay.
There are free advice centres, both govnt and charity/private who are real experts
and will tell you your options .
After getting the facts you may still decide to jump ship. I wouldn't blame you.
But you must find out a bit more first. Your situation - your despair - is too serious to depend only on advice from posters like me.
Good luck
P.S. You may consider, before things get too dodgy with your lenders, opening a small savings account in another bank - and ,if possible, across the border.