Voting should be compulsory too. BUT it should be made as easy, unobstusive, and convenient as absolutely possible to do so, AND the option to not vote for any given office or the whole ballot must be available too (though you are still required to specifically opt out). This makes people far more likely to vote, incentivizes helping that happen but still allows for apathetic/protesting/undecided voters to better represent their desires.

Compulsory voting is not incompatible with proportional, instant runoff, or approval voting. You can do both.

Both. Both are the way to go.

Por que no los dos?

Have been saying for years; compulsory vote with default NOTA option, make a non-vote actually count for something. Tricky part will be figuring out what it should count for. Personally I would want it to be disqualifying for anyone who loses to it.

Having compulsory voting would already improve results from fptp. Proportional voting would make it perfect.

We have mandatory voting here in Flanders and people still overwhelmingly vote far-right demagogues into office…