When you have a better idea, do tell. 
In the one particular case that I’m following most closely, the main non-mainstream party was not created by covid. Based on all published polling data, it is in absolutely no danger of forming government, but it is in significant danger of gaining (re-)entry to Parliament. Also, polls show it rising considerably in recent weeks. The logical conclusion is, people are turning to it as an alternative, whether for “protest votes” or because they want to see it in Parliament. (The state broadcaster published a diagram purporting to show where the new support was coming from: mostly from the party it splintered from a few years ago, but to some extent from all the other parties.)
As I recently pointed out, in a certain other major country there is a new party formed for the purpose of opposing covid measures, but the main non-mainstream party over there also existed before covid and also seems to be popular among those opposed to covid measures in general. The state broadcaster did a ~half hour interview with the party’s big potato (I’m not sure if he’s technically the “leader” or not) that was quite hostile but still civil, and he basically said yes we’re libertarian on covid, deal with it. Like in the other country, this party is not in danger of winning the election, but it will have a voice in the legislature anyway, so at this point people who perceive it as the only credible “alternative” will presumably vote for it specifically for the purpose of opposing covid measures.
So basically people are going to get the choice of the current government (or the mainstream opposition, who aren’t much different), or a government run by QAnon.
Not quite. The main-non-main parties tend to be run by people who have their heads up their dark places just like the other parties, and perhaps a bit farther up, but they’re also professionals, just like the other parties (perhaps slightly less professional, but the proof is in the pudding). They tend to attract real wackos at a higher rate, yes, but that doesn’t mean the percentage of the population suffering from real wackiness will magically metastasize if such parties gain larger representation.
In the US it’s a bit different because one of the main-main parties now has a wacky faction more-or-less in control, but most countries are not the US. 