Thanks for the question!
Since Sunday 5 December 2021, all passengers to Ireland are asked to show a negative test for COVID-19. The type of test required depends on a person's vaccination status. A link to the official information can be found on our traveller health
page. It is still necessary to fill in the passenger locator form
online less than 72 hours prior to arriving in Ireland.
In your case, as a fully vaccinated traveller, you will need either a negative antigen test no more than 48 hours before you arrive, and it must be carried out by a health professional or skilled testing personnel. You can’t test yourself using a lateral flow test. Alternatively, a negative PCR test carried out no more than 72 hours before you arrive in Ireland.
As you say, passengers are also being advised to take daily antigen tests for 5 consecutive days, beginning with the day of arrival (and to self-isolate immediately and seek a PCR test if they develop symptoms or have a positive antigen test). This is not compulsory only advised at this time.
Covid passports are also required to access hospitality, please also take a look at the current public health guidelines
I hope this helps explain the current travel requirements.