You never mentioned where you are now but my sense is a large city in the United States. Maybe north east coast. I’m not seeing a great deal of opportunity in Ireland for you with work and social life.
You could be happy there but you would have to be smart about how you do it. With the ex, I see this person going in a completely different direction in life right now. They could come back but it’s not likely and it will be a while if they do.
But there are relationship opportunities around you. I keep seeing you in a larger US city where there is plenty of culture, social life and people. Have you considered getting over the breakup first, before you make a big decision to move.
I get a better feeling about you staying where you are.