Don't forget putin is actively pushing these parties in the US and Europe. It's not an organic backsliding of societies into fascism, but a concentrated effort
Russia involvement is one thing, but it would be delusional to believe without its tentacles everything would be fine.
It's actually the domestic ruling classes of these countries which are engineering the move to the right, as shown by Silicon Valley beginning to re-platform Trump even before the Butler assassination hoax gave them air cover to go all the way and also get their man JD Vance the VP nom.
Do you have any proof for that except the usual drivel of European politicians of blaming Putin for any domestic problems? The rise of the "brown wave" is natural considering politicians in power have been constantly ignoring domestic problems in favour of pursuing geopolitical agenda.
If you want to see a concrete example of election interference, look no further at recent elections in Moldova, Romania or Georgia and lengths EU has gone in keeping pro Russian politicians to get elected.