Most of these answers lack a broader understanding of the history and systems which produce this phenomenon. There’s a good video that talks through multiple examples of a similar rise in right wing populist dictators and the theoretical through-line that connects them: https://www.youtube.com/watch?v=Q0GQP-IRVqM
To summarize: Privileged classes in a hierarchical society fear popular will turning against them and taking away their privilege, whether by election or force. When times are good the threat of this is relatively low. But when things start to fall apart, people start organizing against the elites. Fearing this, even liberal members of the upper class choose to side with those to their right, because even if they disagree with their more extreme positions, to them it’s better than losing their privileged positions in society.
From there, the right wing uses all sorts of tactics to suppress opposition and cloak themselves in faux populism. Everything from propaganda to direct acts of violence.
Why is the right on the rise in a lot of these social democracies? Because they’re still capitalist, so that structural need to suppress popular will still exists despite their nicer social programs. It was going to happen eventually, it’s just a matter of when. Capitalism and imperialism around the world is reaching another moment of crisis, so this is exactly the time when they’d be doing this.
TL;DR: Surprise! It’s capitalism again!
That and making cold things hot and hot things cold.