I'm not exactly an expert on the Soviet Union, let me just make that clear. There were many Jewish officials and representatives in the Soviet Union. It all depends on when you were alive in the USSR. Lenin and Stalin were fairly internationalist, they hated chauvinism, they considered it a tool of the bourgeoisie to divide the workers. Instead they tried to promote every ethnic group equally and wanted them to get along. Many people living in former communist countries describe there was a sense of solidarity and peace between ethnic groups. After the fall of communism this changed for the worse, especially in Yugoslavia with genocides and ethnic cleansing, but I'm getting off topic.

One of the biggest reasons for Stalin to invade Ukraine was to stop the pogroms against Jews, Ukraine had, and still has, a big problem with fascism. Lenin and Stalin wrote comprehensively on the national question and liberation movements.

Things changed under Khruschev, he promoted Russian nationalism, this is why communists in modern day Russia are still very nationalist. Anti-semitism was more present during his rule and after that. Of course, antisemitism was always present, especially in rural areas, but before it was seen as anti-communist, under Khruschev it became more acceptable. Hope this helped.