Wow, what a destination. The Gold Coast is home to the infamous Schoolies week as well as known as Australia's answer to Vegas. I have driven through the Gold Coast on my east coast trip in 2018 but didn't stay. I was excited at the idea of spending 5 days exploring the gold coast.
First thing you should probably know, your accommodation options are mostly apartment style hotels or home stays. It's not often you'd see a hotel. There are hostels around as well. If you're thinking of coming the the Gold Coast I would suggest Summer and a weekend is going to give you the best experience of what the GC has to offer.
If you're wanting a high rise apartment, most are 2-3 bedrooms and can cost a little more than most. It's worth asking to see your options but if you're looking at a one bedroom then you will most likely be on the lower levels.
The Gold Coast offers a great list of things to do apart from the beach that lines the city. There is shopping, cafes and restaurants, nightlife like I've never seen as many ways to explore the city on foot.
I would suggest hiring a car if you're going to be staying for more than 2-3 days. You can drive down to Byron Bay, explore the city by car as well as take a look at the surrounding beaches. A day can set you back $40-70 on average a day. It's pretty fair pricing to be honest and if you're younger than 25 there might be other premiums not included.
As much as I loved the Gold Coast there isn't much to say more than you need to explore it on your own at your own pace. It's got many things to see and do but although we spent most of the time in the apartment because the weather was a little unpredictable I was fairly satified just looking at the view and unwinding.