It is really difficult to determine "is it hard to get x atar with y subjects and w scores" simply because of the change in abilities/exams each year.
Having said that, an atar of 80 is DEFINITELY within your grasp.
You do not have to be that smart to get an atar of 80 (let me explain) you just have to be committed and dedicated to your studies. Sure, talent in a subject will drive you well, but some things in life (a high ATAR as one of them) not necessarily goes to the most intelligent people but the ones that are able to be 'smart' in exams. Trying hard and getting help where need be, you know, all the stuff your teachers always tell you.
Be confident and believe in yourself and you will find you might very well get an atar above 80. It may not be an easy path, but set yourself goals (short and long term) and stick to them, youll be amazed with what the results are!
Best of luck and just know that in you, you have the capability to get well above 80.
Always here to help if you need 👍🏼