This, especially whats in bold - most people who study and stress for a super high ATAR when they only need something small end up kicking themseleves when they get to uni.For a 72 ATAR, a person with average intelligence.
1) needs to do all their classwork and be productive in class
2) Do their homework
3) Do cramming before assessments
A 72 ATAR can be gotten without consistent studying effort. But that said, do a decent amount then you can't regret it later by "if I put a bit more effort in, what if???" but don't kill yourself with study and stress when you only need a 72 ATAR for what you want.