It's worth noting that the aircraft that QF are now sending on BNE-LAX are A332's, which have slightly longer legs than the A333's.
Rumour has it that back when QF was reconfiguring the the 330's with the new business class (circa 2014?), management intended the 333's to be international-only aircraft, while the 332's would only do east-west (and the occasional short Asia / NZ crossing) . Two of the 332's (EBG and EBL if memory serves) were kept in a long-haul config, however, mostly for AKL-LAX-JFK and India services via DRW - these birds were the ones with the sloping skybed's 1. The 333 was configured with a more long-haul setting (i.e cloth seats v. leather in business and, most importantly, a significantly more comfortable / spacious economy product).
This is didn't work out for a couple of reasons: 1. The 332 has longer legs than the 333 (for instance, PEK and BKK possible on a full load for the 332 however may have some load restrictions for the 333) and 2. The resources boom went bust, meaning that trans-con demand shrunk right back down.3. The 'international' a332's were getting very, very old. Qantas got stuck in a bad spot, however, with recently-ish configured aircraft that weren't right for the market (the A332s).
What Qantas then needed to do was to create a minimally-edited aircraft that would work on long haul - with more galley space, pilot crew rest etc. What they settled on was ripping a couple of rows out of the trans-con A332's that had hard-wired IFE (i.e not the iPad streaming aircraft), chucking in a bit more galley space and a pilot crew rest, and calling it a day. Post-pandemic, these aircraft are operating a fair chunk of the Qantas international network - including the BNE/LAX rotations.
The problem with this is that you now have an aircraft with an economy seating product designed for max 5 hour sectors (effectively short haul) crossing the pacific. The seats on the A332 are significantly different to the A333 - closer to what you see on the 737.
Long story short - avoid Y on this flight at all costs.