That's a simplistic view with regards to whether Jews in 1930's Europe did want to leave en-masse. As soon as you had the Nazi's rise to power there were many Jews looking to flee Europe...
No, there was a relatively small number of Jews looking to flee
Germany. (Also a very small number looking to flee Italy, but later, as Italy did not enact anti-Jewish racial laws until after allying with Germany in 1936.) Some went to the U.S., but most went only to other parts of Europe. E.g. the family of Solomon Perel, protagonist of the docudrama film
Europa, Europa. They left Germany after Kristallnacht - for Poland. And note that they didn't choose to leave in 1933, i.e. "As soon as you had the Nazi's rise to power..." Few Jews realized what Nazi rule would lead to. Most thought it would be like many historical episodes of anti-semitic frenzy: a few years of beatings, vandalism, occasional murders, confiscations, legal discrimination - a storm that could be ridden out. And that was within Germany. Even fewer non-German Jews perceived a danger that justified abandoning one's ancestral home for a distant country.
and certainly into the prelude to the war you would have had Hitler actively encourage Jews to do so.
But that only affected German Jews (and Austrian and Czechian Jews, to be sure, though only in in 1938-1939). Most of them did in fact emigrate before the war. This group amounted to about 500,000-700,000, and of those that emigrated, only a fraction even tried to go to the US.
Not to mention the vast majority of Russian Jews not in positions of political power still had to deal with the centuries of ingrained anti-semitism lingering in the Russian sphere.
In terms of anti-semitism in Russia, the 1920s and 1930s were a period of enormous progress. All discriminatory laws were revoked. Jews were free to participate in every sphere - arts, industry, science, the army, the academies and professions - without restriction. They were free to reside in any part of the country. Residual anti-semitic prejudice persisted, but its real comeback was much later - in the 1950s and 1960s. (And even then, it was
sub rosa - a far cry from the Tsarist era, when the Black Hundreds ran wild and the
Protocols were disseminated by the state.) There certainly was nothing in the 20s and 30s to cause millions of Jews to emigrate.
I can't speculate on the concrete numbers but you certainly would have magnitudes more Jews enter the US throughout the 30's and 40's than IOTL if not for the restrictions.
Immigration of all sorts declined precipitously in 1929-1933, and remained very low till after WW II, when it rebounded to merely "low". This decline happened well after the restrictive laws were passed in the mid-1920s. Those laws substantially reduced immigration, but it was the Depression which choked it off almost completely. I do not know how many Jews immigrated to the US in 1930-1949, but 10x or 100x ("magnitudes") is highly unrealistic.