I also was a customer of Bank of Ireland and found them quite good, online agents were very professional and responsive to queries, and despite what others say, I saw no problem with their online app but decided to leave when my current account annual fees increased from €20 to € 72. I moved to KBC which are also excellent.I suppose you pay for what you get.
As regards N26 my experience is that their customer service is mediocre. The agents on the chat function are very hit and miss, sometimes give incorrect information: for instance one agent insisted I had applied to open a standard n26 account when it was a premium n26 "You" account. Another two agents insisted only " Metal" premium customers have access to the phone service whereas " You " customers also should have access according to T&Cs, but this phone service is NOT in service when you ring the Irish number and I tried several times but it says "out of service" . In my experience Human Agents on the chat often dont answer specific questions put but send links or avoid answering unless you repeat the questions. Chats can be quite protracted and non- premium customers can have long wait times. They can also terminate chat abruptly before issue resolved. This happened a few times.As regards e mail you will wait a long time to get a reply. I also have read reviews on Google and trustpilot saying accounts can be suddenly closed and other comments echoing what I have experienced.
It is quite difficult to open an account: Passport ID has to be photographed and uploaded several times before accepted( eventhough images are crystal clear). If you have to video -chat an agent to verify ID they can be quite abrupt. I tried to help an elderly friend with this and eventhough I wasn't in video chat once agent heard me in background they said they would terminate call. My friend had difficulties in hearing what agent was saying. The agent even mentioned " prosecution" which was ridiculous. The agents are apparently Berlin-based.
On a positive note I signed up for a n26 you acvount. It costs €9.90 per month ( but I got it free with a voucher- this offer is now over) and the account provides 1 years Allianz travel insurance. I'm not sure this account is worth 9.90. I certainly wouldn't pay it.They charged me €9.90 the minute I credited my account with funds.I immediately requested a refund and received it.
I used the Mastercard in London at both ATM and contactless and it worked perfectly despite others saying they had problems. (You will have to pay €10 for physical card unless premium customer or use google pay)The instant transaction notification are quite good, especially in a foreign country or online.The app is easy to navigate. You can set atm withdrawl limits, stop online transactions or stop overseas transactions. These are excellent facilities not on Irish banking apps.
Negatives : mediocre customer support if you have issues. No person to speak with or call in to unless living in Berlin.
I fear this is the future of banking in general. All online, no branch network, & nobody to speak with or see face to face if you encounter problems.
I was going to use N26 for my principal banking after KBC leave ROI but I have now decided not to do this. I would recommend OP to keep an Irish Bank account open.