Only to add to the helpful responses you have had, I have frequently transferred at Sydney to Brisbane. The last 2-3 years, I’ve experienced long waits for bags - 45 mins or so. Priority does not count for much at Sydney. Best to get your skates on for the transfer to the Domestic terminal, if you experience the same. The good news is that Qantas domestic boards at 20 mins before departure, on the dot without exceptions in in my experience.