Robin Go to the Home page in the bunq app, tap the "More" button in the bottom right corner, tap "Add sub-account" and choose "Local IBAN".
Your account was opened with a Dutch IBAN, because bunq is a Dutch bank.
Your plan, Easy Bank, only includes 1 account. However, if you open an Irish IBAN, it becomes your second account, so you need a more expensive plan (Easy Money, β¬8,99/month).
I think the best option is to contact bunq support, or open the Irish IBAN and then contact bunq support (Profile > Settings > Need help) to ask for a β¬6 refund. Because it's not possible to first close your Dutch sub-account and then open the Irish sub-account.