You have 2 stopovers and 4 segments in Oz and 12 months to complete the trip. Can be open jaw. Start in SYD and finish in BNE for example. With a little planning you can get a trip /stopover to somewhere in Oz effectively for next to nothing

Instead of
BNE-SYD-LAX-SFO-DFW-ANC-ORD-LAX-JFK-LHR-FRA-LHR-SIN-MEL-SYD-BNE

Purchase BNE-SYD separately and then
SYD-LAX-SFO-DFW-ANC-ORD-LAX-JFK-LHR-FRA-LHR-SIN-MEL-BNE-DRW-BNE
Stopover’s in BNE and DRW

I took 360 days to do a RTW, with a 9 month stop over in home town

And for more SC’s
SYD-JFK-BOS-SFO-DFW-ANC-ORD-LAX-LHR-FRA-LHR-SIN-MEL-BNE-DRW-BNE

BOS-SFO = 2704 miles (above the 2700 !!)
Au to US east coast and US west coast to LHR maximises miles and SC’s

Also AA has serval flights to FRA, like DFW-FRA at 5143 miles

Maximising SC's and QF flights
SYD-JFK-BOS-SFO-DFW-ANC-ORD-LAX-LHR-FRA-LHR-SIN-HKG-NRT-MEL-BNE-DRW-BNE = 17 segments (NRT-MEL = 5060 miles:- above the 5000 miles.