UAC: will the first preference “block” others?

Hi,

For my five preferences, the first one is USYD. I’m confident about all my other options except for the first preference—USYD.

Should I avoid putting USYD as my first preference? I’m worried that this might “block” all my other preferences in the first and second rounds. For example, if I don’t get into my first preference, would my second preference even have a chance to be considered? Is that correct?

Maybe I should move the less likely option further down on my preference list to receive offers from other universities first, and then move it back up in later rounds? That way, I can at least get more realistic offers.

Is this the right approach?

Thanks!