Roaming in New Zealand

We're planning on going to New Zealand early next year, and I wanted to see if anyone has a recent roaming report to share. We're on Go5G Plus, so we have 5 GB of high-speed data, which ought to be enough. I don't know yet if we'll be on the north or south island yet. I know coverage can be spotty in rural areas, but I wanted to ask about how spotty it is and also about data speeds when roaming with our plan vs either getting a travel eSIM or one from a local carrier.