Richard:
I am going over next week, to check in on St. Patrick's [which I haven't seen in 18 months] and then to The Renaissance Club.
As of today, if you are vaccinated, you must quarantine in one place upon arrival in Ireland for at least five days, after which you can take a COVID test, and if negative, you're good to go. You are allowed out of quarantine to exercise each day, but I don't think they'll accept you being on a golf tour as "exercise". I believe it's wishful thinking that the quarantine rule will change before the fall, but your guess is probably as good as mine.
Also, as of today, once you have been in Ireland for ten days, you may fly to the UK without any COVID test or quarantine restrictions.
P.S. If you go to Ireland and choose The European Club over St. Patrick's [which is about two hours from Portrush], you will have made a mistake.