People are getting tired of corrupt authoritarians.

Some countries may go the other way though. So it might be people getting tired of governments that don't get the results they want, anti-incumbency if you will -

where populists have ruled for long periods (Hungary, Serbia, Brazil), public fatigue tends to build against political capture, corruption, and state control. Bulgaria somewhat fits in here as well although there, people voted in a Putin-friendly strongman (which has been appreciated by Putin sinking a couple of ships in the Black Sea, in front of his coast).

where establishments have ruled, centrist or liberal (France, Canada, parts of Western Europe), fatigue tends to build against economic insecurity, immigration friction, and technocratic governance, clearing the path for right-wing populists. Oddly enough, Le Pen who is in the lead for president wants to do more of the same what Macron did (and currently gets vilified for) - public spending cuts, tax cuts for businesses - except she also wants VAT cuts, and keep retirement age at 60 or 62, without any credible path to finance all of that.