You do not need a transit visa
You do not need a transit visa to travel through an Irish airport on your way to another destination.
When you arrive in Ireland, you will remain 'airside' of the border while you wait for your connecting flight.
You must apply for a short stay Visit Visa if you want to pass through border control, eg if you are transiting overnight and want to stay in a hotel.
If you do not have a short stay Visit Visa, you will not be allowed to pass through border control.