Hopefully this is still useful to you. My experience is focused on NI and Donegal - I'm not sure about further south (expect Dublin & Cork would be much better though).
There are no Superchargers in NI, though one is scheduled for the Belfast service centre later this year. And a distinct lack of >50kW chargers in the north compared to Scotland. A few destination chargers dotted around too.
Headline: ESB eCar is going to be vital for you - almost all rapid chargers are run by ESB, in both NI and the neighbouring counties of RoI. It's generally free of charge in NI, but generally chargeable over the border.
Make sure you have ordered an RFID card from ESB - don't just use your phone. Some of the chargers have communications issues (e.g. the charger at Glenshane Pass on the A6 between Belfast & the north west), and an RFID is the only way to start/stop charging in these situations.
Having said that, the ESB eCar app is pretty good.
It's worth having a 3-phase cable, since there are a fair number of 22kW AC chargers in town centres that you can use at 11kW that way.
