You're not wrong, but you're giving right-wing populists too much credit. Their polling numbers are not just a product of their own efforts, but equally so the result of

• outside interference: Russia is probably one of the most prominent actors in this sector, linked to both interference in U.S. elections (on behalf of Trump), in the Brexit referendum (on behalf of the Leave campaign), in the latest Romanian election, and so many more. But technofascists like Thiel and Musk are equally getting involved, endorsing, hosting and probably bankrolling candidates they see as conducive to giving even more power to oligarchs. Cf. Musk hosting and endorsing Alice Weidel (AfD GER) and Tommy Robinson recently at the London rallye, and Thiel essentially funding JD Vance's entire political career.
• the abandonment of the working and middle class by the political elites: hear me out, I'm not just parrotting a right-wing talking point here. If you look at the development of both income and wealth inequality in the last few decades, you'll see that there is some truth to it. Governments from left to right have had a much more open ear to the interests of corporations and billionaires - after all, that's where all that sweet, sweet campaign money comes from, as well as the career for their lives after politics. Meanwhile, ordinary people have been struggling from crisis to crisis: from dotcom bubble to subprime meltdown, from the Euro crisis into a global pandemic, and from there into two severe energy shocks ('22 and '26). And it turns out that bailing out banks while dishing out austerity, shutting down the country and remaining mostly inactive in the face of rising inequality and inflation isn't exactly the way to win the trust of the public. That said, the far right posing as an "alternative" to failed mainstream politics is a joke, obviously: as laid out above, they are mostly bankrolled by the very elites that are responsible for people's struggles. They are here to shift the blame onto marginalised groups and give even the lower classes somebody to look down and vent their anger on. If you look at their agenda, their plan is to open the floodgates even more to the money elites, slash taxes and regulations and funnel government spending towards oligarch-owned monopolies. (The rampant corruption under Trump II bears ample testimony to that.)

So, yes, the far right has been busy in the recent past. But they wouldn't have come this far if it weren't for fascists with money supporting them and mainstream politics failing people left and right.

To me, I think they have spent years and years coordinating (not just in Germany) with other right-wing parties, tried and tested propaganda mechanics, nailed the language, the target audience, sold the product properly and their target audience responded.

Which is what any party should do, they did nothing new or strange, they simply listen to the people and offered solutions (which would not necessary work or be realizable) occupying a space other parties decided to abandon.