Travelling between Xi'an and Adelaide - hmmm - if you value your time by doing it one stop only - that means stopping either at Hong Kong or Singapore. The logical carriers to use in the future would be Singapore Airlines Xi'an-Singapore-Adelaide or maybe Cathay Pacific Xi'an-Hong Kong-Adelaide, depending on connection times that suit you.
There are of course many many other options with 2,3, or even 4 stops if you prefer. such as through Sydney, Melbourne, Beijing, Seoul, Shanghai, Tapei etc etc
But assuming you fly CX (Cathay Pacific) it would make sense to join CX's loyalty scheme Asia Miles or maybe credit the CX flights to your existing Qantas freq flyer or
if flying SQ (Singapore Airlines) it would make sense to joining SQ's loyalty scheme Kris Flyer or join Virgin Australia Velocity frequent flyer.
It seems that either way - if you are travelling in and out of Adelaide then Qantas is not interested in your business it seems.