Politics in Ireland has been complex for a very long time.
Every person I have ever met from Northern Ireland or Eire has been delightful. I had no idea whether they were Protestant or Catholic! To me, it does not matter.
What may change shortly, following May elections, is the First Minister in Northern Ireland may be in favour of rejoining Eire. The unionists, who identify as British, would hate this. Whatever happens in the future is complicated. BREXIT made matter worse.
I do not have answers.
There is some logic in becoming part of Eire, but I can understand the fears of the Unionists. Hopefully a solution can eventually be found that keeps everyone happy.
Will this happen in my lifetime? I doubt it.