I mean, Hitler never got a majority with the NSDAP. I think he actually got like 30% of the vote or something, and became the biggest party, but far away from a majority.

The issue was that the centre-right parties were scared of the left-winged / communist parties, so they decided to cooperate with Hitler.

Basically, it’s usually centre-right politicians that give rise to radical right politicians, and the radical right politicians don’t need a majority, to get into power.