The partner publishes a first deposit bonus of 600% cash, daily cashback of 10% of losses, a minimum deposit of US$20 and a maximum bet on a bonus of A$5. The last figure matters most: if you take a bonus, your stake is capped, and a high-volatility game on a capped stake takes longer to reach the spins you are waiting for. Cashback is calculated on losses, so it is a partial cushion, not a rebate on turnover.
The published return and the 5,000x maximum are the two numbers to hold on to, and neither is a promise. The return is an average measured over a very long run, and the maximum is a ceiling that the overwhelming majority of sessions never approach. Bring a stake you can lose without it mattering, and decide the stopping point before the first spin rather than during a dry run.