Taking into consideration DL's last statement, it indirectly tells the reader that DL is not interested in any Australian port out of SYD. DL 'may' look at another one of their hubs outside of LAX (e.g ULR from ATL, or SEA-SYD), but that's as far as it goes for DL's own Australian ops.
Unless if UA somewhat out of the 'blue' buys a stake from Bain, VA and DL are basically stuck at the hip.
Keep in mind that a JV means both carriers have to SHARE the costs, so if they make money, it's 50/50, if they both lose money, they lose 50/50.
So it'll be either SYD on their own with a VA codeshare (should VA chose to leave long-haul entirely at the end of 2022), or if VA choses to re-enter longhaul, a reactivated JV with VA doing MEL/BNE-LAX. All that it basically needs is 5-6 leased widebodies (4 for US ops and 1-2 for Asian medium-haul ops).