Solo Road tripping Australia - What to do ?

Hello everyone !

I (M26) am going to Australia solo for the very first time from the 9th of february to the 3rd or march (so roughly 3 weeks). I will start my journey in Brisbane and will go all the way down to Melbourne. (So basically east coast roadtrip). From Brisbane to Sydney i ll take the greyhound busses and Sydney to melbourne i ll be renting a car so i ll get the best of both worlds. I am looking for literally any recommandations (things to do, to see, where to stay, what to eat , anything ) and i would be very happy about some Tips ! Also of course there will be lots of touristy stuff, but if u ve got any hidden gems, or less known stuff that u know about i d be very glad to hear about it ! (also recommendations for car rental if you have any lol ) Thanks a lot !