Qantas do a good job of transferring bags between two separate quasi-connecting bookings on their own metal, if asked nicely. However absolutely no dice getting them onto another oneworld partner’s separate quasi-connecting booking

BA won’t even do it on own metal (as a rule, no doubt exceptions are made from time to time)

it’s basically the norm now that separate bookings=separate baggage handling. Anything above that should be seen as a bonus not a right IMO