Good luck, it's hard to find availability in business on points and even harder to find
reasonable points availability. That said, I'd consider the main US carriers-DL, AA, and United. I know a pp has mentioned Alaskan and Hawaiian-I could never find Alaskan availability and Hawaiian just wasn't an option for me, so I'm not the person to discuss those. Also keep in mind others like Singapore Air, Air Canada Aeroplan, etc.
It's also important to accept that a positioning flight (unless you live in the Bay Area, LA or Honolulu) is almost inevitable.
I'd also consider two one ways v. round trip since different carriers open up points availability at different times.
Is this a once in a lifetime trip that using most of your points is worth it? If so, then read on (I can spend points/miles with the best of them
).
If I were looking at flying to Sydney and home from New Zealand today, with your points, I'd probably either transfer a hefty amount to Delta and do LAX-SYD on Delta (right now far enough out that would cost 730K Skymiles-eek-for 2) then focus on United and try to fly back premium economy (approx 250K for two) or business (approx 400K for two)...or look at Singapore and try to do both flights with them (quickly checking it looked like around 350K from AKL- LAX for 2 in business and slightly less than that for 2 LAX-SYD with stopovers both ways in SIN).
Prior to our flying to Sydney in Feb 2020, I'd forecast the need for 1M (!!!) skymiles for the trip and then 400k United back from NZ. Delta has actually slightly decreased the award cost (for now) and United has stayed the same (knock on wood). I ended up not flying either which goes to show it's important to have more than one plan.
The flight to Australia is longer than the flight back (about 90 min if you're going to/from LAX) so if you had to choose one flight for business, I definitely recommend the flight TO Australia versus the return. We flew Qantas F to Sydney and it was amazing and SO MUCH better than the flight back from SYD on Virgin Australia in business (DO NOT RECOMMEND).
Hope this helps and have fun planning!