Let's start from what could be improved and why on...

Let's start from what could be improved and why only 3 stars:
The room had damaged bathroom door which didn't close.
The air conditioner was not working. I didn't see any result of switching conditioner modes and setting higher temperature also didn't work. I felt cold.
The bathroom vent worked all day and pushed cold air into the room. It can't be turned off.
I asked reception why it doesn't stop and they answered something this was for safety measures. However, could not clarify what is connection to this air vent with constantly pushing cold air and safety measures. What is safe about constantly working central ventilation and pushing air to the rooms ? Helping the virus spread from one room to another? This looked unclear and ridiculous.
The room walls were a bit dirty.
I didn't like that I was charged in advance in the 4 star hotel.
When I stayed at Golden Tulip 4 star hotel in Netherlands I paid only at check-out after a week. No one suspected me that I can't cover my costs. And also no one registered there for breakfast. Only asked during check-out how many breakfasts did I visit to correctly calculate price.
I know what is great service and hence I can value the quality.
The overall quality is far from Netherlands or Sweden 4 star Hotels.
The breakfast was just okay, I would say average, not brilliant as Booking advertises. Not as good as Swedish Hotels have. However, that quality of food is quite common in Ireland. So for locals that may be just fine, but for those who know a better level, this will be noticed as is.

What was good:
Nearly all personnel at reception were friendly and smiling. Everyone helped with any question, like taxi ordering, etc.
I saw hotel had started to roll out new safety standards for restaurant.
Those could be improved though and manager promised to improve them even better, making hand cleaning tube clearly visible near the warning about safety measures, otherwise it was hanging somewhere on the side and could be easily passed by.

I must admit that Hotel has had problems working and delivering service in such difficult situation with virus epidemic in the world and in the country. I with the hotel to improve even better and reach the level of quality like hotels of Netherlands or Sweden, which have also a lot better and more different food for breakfast.