I think the UK will soon lift it from the EU and some non EU countries so ROI will probably have to do it otherwise people will just go XXX - LHR - BHD . The Antigen / PCR requirement crushes the travel industry and does very little to stop cases. In Ireland its rife never seen so many people who I personally know get it and some have had it twice in 2 months . First Delta now omicron .
Thankfully Ive avoided it so far . Cant get PCR tests via state system and LFT kits sold out in most pharmacies and stores. Free in the UK and people who live around the NI - ROI border are getting their family / friends and colleagues to order the NHS ones and bring across the border.