I can probably answer in terms of Business Studies. Having gone through some of Girraween High School's year 12 assessment tasks (because I was helping a student from this school with their assessment), I personally felt that the difficulty of their assignments (relatively high) would be a good indicator of the teachers' commitment to teaching and student success.
There are good teachers and bad teachers within every school, although percentages do vary across schools. When considering a school like Girraween High School that ranked 27th in 2020, I think it would be correct to assume that a significant percentage (if not most) of the teachers will be competent and able to demonstrate effective commitment to student learning and success.