some unis do it seperate to UAC, such as wsu uts uow. Through this you can apply to as many as you want. Other unis like unsw and usyd only offer to certain demographics of students
there are some internships which operate mid year when unsw is in t2, whereas other semester based unis are on break. I wouldn’t say this is so much an issue however, it is one of the best unis especially for what you’re looking at.
you’ll miss out on some internship opportunities at UNSW because of the trimester system (winter). Also note that first year subjects at the two unis vary quite heavily and if you were to transfer from UTS to UNSW, I wouldn’t be expecting many to be credited.