Substantial gains. The Nazi regime damaged technological progress in many ways. Merely driving many of Germany's best brains out of the country (because they were Jews or socialists or just not-fascists) caused much disruption.
Then there is the effect of the war Germany started, which killed millions of people, including lots of potential scientific and technological contributors. These deaths were substantially concentrated among technologically proficient peoples - Germans and Japanese, and also Russians. (At that time, China and India didn't really count in science and technology.) Among Americans and Britons, men with the qualities of technical elites (intelligence, math skills) were selected for air operations and suffered disproportionate deaths.
Then there is the horrific effect of the German mass murder of Jews. OTL, roughly 25% of all Nobel prizes in the sciences have been awarded to Jews. Hitler killed about half of all Jews in the world.
So without Nazi Germany, without World War II, without the Holocaust - unquestionable technological progress would be farther.