Lets try and avoix making this political topic eh.
RNLI's first station in Ireland was opened in 1826. The RNLI is a registered charity in Ireland the Republic of Ireland 20003326
The records appear to show the main income , over 10, 000, 000 €, comes from donations. A friend of ours worked in the RNLI shop at Youghal and reported on the generosity of the locals in funding the service through donations, fund raising events etc.. Can't see anything there that shows that the RNLI in GB sends money to Ireland.
https://www.charitiesregulator.ie/en/information-for-the-public/search-the-charities-register/charity-detail?srchstr=20003326®id=20003326