IF you were so interested in preventing the next Hitler what you would actually have to do is to rigorously oppose anything that threatens the livelihood of average people. Fighting inflation would be THE number one concern because you'd know that people carrying their money in wheelbarrows was what caused Hitler.
If you want to prevent Hitler, you'd fight like hell for decency. Homeless encampments? Open air drug dens? Only-fans? This would be your concern because you'd know that in the Weimar Republic rampant prostitution and other cultural decay is what caused Hitler.
If you wanted to prevent Hitler you'd also speak out sternly against Antifa and other violent extreme leftists, like those that caused the George Floyd riots, because you'd know that the breakdown of public order due to rampant political violence in the Weimar Republic is what caused Hitler.
Nobody on the left is doing any of that because nobody on the left really thinks Trump is a Nazi. It's just a label, just a tactic. And all it has done is to burn term. Trump or Maga or the current right reaction isn't the big bad. What comes after this might be, if Trump fails. Ironically, it's exactly Trump's agenda which is most suited to fight real fascism.