Are you not allowed to submit an empty ballot if you like? I thought that was an option in all countries with mandatory voting.
Sure you can do that. Once they mark you off the electoral roll, then you're covered for the obligatory part. Nobody manually checks how you filled out your vote.
Looking through this list of candidates (at least it's just a local election) is pretty bleak. There's the Animal Justice Party, which I am unsurprisingly putting at number one (I can't be arsed explaining our strange voting system, to put it simply you number all candidates 1-10), but all of the other options fail to align with my own values very much at all from what I'm reading - and as far as I can gather from what I've read in the past about this arcane voting system, the weight of your vote basically goes to the first candidate in your preferences that would end up with enough votes to win overall.
It's called a
better voting system. See Cpgrey's election videos to see why.
The reason it's better is that it doesn't suffer from
splitting the vote. e.g. say there was a left-wing guy with 60% support, and a right-wing guy with 40% support, then obviously the left-wing guy should win. However ... say there was also another left-wing guy who's about as popular as the other left-wing guy, e.g. 60% of people like them more than the right-wing guy. Being
logical the winner
should be either left-wing guy A or left-wing guy B, since those two guys are the most popular candidates. However, that's not what happens. In the First Past The Post system, each left-wing guy only gets 30% and the right-wing guy gets 40%, meaning he's the winner, even though a majority of the population would have preferred literally
any other candidate.
e.g. we're running an election where Alex always beats Bob, but if Charlie decides to run as well, suddenly Bob wins. However ... if Alex drops out, and only Charlie is running against Bob, Charlie always beats Bob. The ranked voting system used in Australia avoids this sort of paradoxical thing happening.