I need to book a trip in Aug 2023 outbound NYC-AKL and return PER-NYC. Client is paying for economy and I can pay to upgrade (REALLY don't want to do that trip in coach!). I'm PM with 400K miles, but all Delta options are JFK-LAX-SYD-AKL (SYD-AKL is on LATAM) and PER-SYD-LAX-JFK (PER-SYD says operated by Virgin Australia, which I didn't think was possible anymore). Either way, Air New Zealand has a nonstop JFK-AKL and then PER-AKL-JFK that's around the same price as Delta (~$2400). That's much more appealing, especially with their interesting "skycouch" option, which seems totally worth the extra ~$2000 for nearly 40 hours in the air. It would be worth it to me to take the longer Delta option if I could pay with miles (I can still bill the coach price to the client), but it says "no results" when I search the trip with miles. If I use dollars, Delta upgrade for that price is to premium select, which I don't think it as comfortable as the 3 seats you get on the ANZ couch product.

I fly Delta almost exclusively and have never flown ANZ. I hate to give up earning Delta miles / MQMs for this long trip. Any suggestions on maximizing my earning options? I have Delta Amex Plat and a business Amex Plat. It looks like I can enter a Virgin Flying Blue number when booking with ANZ. I just signed up for a Virgin account. I suppose I could earn those points for the flight (how many?) and then use those for maybe one Delta r/t in the future? Of course I don't earn MQMs for that, but it's something. Of course I'll use one of the Amex cards (not sure which would be better). Anything else I'm not thinking of to maximize my benefits from this trip? Any other thoughts on this trip?

Thanks so much!