You are not only entirely misunderstanding why the NSDAP appealed to people, you're also completely misunderstanding what post WWI Germany was - a republic hastily brought about with little care so that Woodrow Wilson would offer Germany peace based on his 14 points (he didn't). It was doomed to fail from the very beginning. If not the NSDAP it would have been some other extremists.
The idea that freedom of speech was what led to its downfall does not stand up to even the smallest scrutiny. Or the idea that an aged, pacified 2026 Germany would immediately return to 1930s Nazism if they had free speech is even more ludicrous.
same goes the other way, Germany can return to 1930s in the time one political campaign starts and ends given the state of society at the moment.
I am not advocating for limits on free speech, I am a free speech absolutist. and with that come the consequences we see not just in the united states but around the world. but to think that allowing anyone to say anything cannot lead to absolute catastrophies/hatred/... in the year of our lord 2026 is very misguided...