Australia

I'm not saying the following to argue, but to add caveats and challenge assumptions.

Not wrong, but all over the world does not have compulsory voting

I see some other people treating compulsory voting as an anchor, but we're seeing a prolonged shift away from the dominance of Coalition and Labor. We're talking about a reactionary politician promoted by plenty of mainstream mass media outlets with astronomical funding - many casual apathetic forced-voters will be exposed to more of her populist policies and less of her terrible perspectives and Gina-service than we see. Especially if everyday people like us don't talk to people about it.

Add to that a high proportion of immigrants

Many immigrants will vote for One Nation. It sounds unintuitive, but there are plenty who openly support Hanson. They've already immigrated, and might trivialise the racist attitudes of the party in support of other gripes, especially if they feel association with Australia and see themselves accepted as "one of the good ones". One Nation is a racist party, but as a whole, it's selectively racist: they will back candidates from most non-Arab ethnicities and have elected immigrants [admittedly not the best example].

a solidly left leaning younger demographic

Yes, but that doesn't outweigh the larger, solidly right-leaning older demographic. Unfortunately Wikipedia haven't updated their table since 2016 and I cbf summing the numbers on the ABS population pyramid, so I'm happy to be contradicted.

Also consider that (judging by the first line of the ABS 2024 age/region summary plus my own assumption) younger populations are likely to be concentrated in cities, reducing the influence of a young vote on suburban and rural electoral seats.

and Trump’s example

And that's been a useful tactic in dissuading ON prospectives, according to GetUp!, which to me also implies that plenty of people don't recognise the similarity of Trump's USA and Pauline's ON.

So, my perspective is, we should be optimistic and confident, but we must not be complacent and passive. These points you make only work if politically-informed people share our knowledge with the apathetic. And this doesn't have to be preachy or direct, even passive exposure and "didjyahearabout" conversations will accumulate.