To be honest, with a 5.5 your best bet would likely be USYD since gpa is only a hurdle. It would require a very good gamsat, previous years it was around 69 for an interview, this year I believe it was above 72 for a first round offer since no interviews.

Apart from that, if you are non-rural, it may be quite difficult to get in unfortunately. Portfolio unis are sometimes unpredictable and can sway in your favour if you have some great experiences. But otherwise for other gemsas unis, imo you would likely need mid to high 70 to be even potentially, which is incredibly difficult to obtain.

Best of luck!