I reckon aero-dynamics will be improved by EV truck makers - you simply can't afford to waste energy/range by dragging turbulence down the road.
My old man used to drive trucks - he said it was quite noticeable that less throttle was needed when drafting another truck or bus, however conversely he reckoned the extra throttle needed when another truck started drafting him was noticeable. Myth Busters did an episode on drafting trucks.
Tesla are making an announcement in September about their future semi-truck offering.
The "Nikola One" is also now emerging. It's electric, but fueled by hydrogen fuel cells. The range claimed for it is 1200 miles. That would be most of way from Auckland to Christchurch, assuming SH1 re-opens in the next year or two. This could be a valid application of hydrogen fuel cells as long-haul trucking companies may be able to stage depots at 500km intervals. The gear for making the hydrogen and storing it is really expensive, but a large organisation might be able to justify ot over time due to the cost savings and performance improvements.
Or just put it on a train.