What is your travel pattern? Premium cabins or economy?
Qantas is generally easier to earn status if flying premium cabins, but if you're not flying to Australia, you won't get the required 4 QF sectors.
CX is generally hard to get status regardless of cabin flown.
If you won't fly BA, then likely your remaining option is AA which doesn't require any AA metal flying.
I have heard AY is relatively easy to get status, but I haven't done the maths myself.
I fly PE when it’s not massively different in price from Y. It’s company dollar but I try to be careful with it.