Russians exterminated them. When Russians invaded in 1939-1940, they abolished Jewish cultural autonomy, closed all Jewish institutions (schools, associations, etc), rounded up Jews into cattle cars and sent them in entire families to die in Siberian wilderness, because they saw wealthy Jews as kulaks and oppressors of the working man. Russians targeted the entire professional class that was capable of running a country (public administrators, lawyers, engineers, doctors, merchants, etc), but because Jews were overrepresented in middle-upper classes, they got hit the hardest. They were about ten times more likely to get victimized by Russians than anyone else.
> Baltic Germans?
Resettled to newly-occupied Poland between late 1939 and early 1940 under agreement between Germany and the Soviet Union. They were allies at the time and had divided Europe in the secret protocol to the Molotov-Ribbentrop Pact. Russians gave Germans free hands to do what they want with Poland and in return, Germany picked up Baltic Germans from the region (in an action called Umsiedlung) and left the rest for Russians to maul.
> Baltic Russians?
Exterminated during WWII by Russians. For example, one third of the pre-war population of Narva was Russian. Russians systematically destroyed Narva in WWII using the same methods we now see in Ukraine. Not a single habitable building was left. After the war, they banned the few surviving former inhabitants of Narva from returning. Instead, they resettled the area with ethnic Russians. This has caused incredible cultural discontinuity. I just finished reading memoirs of a Russian who grew up there in the 1960s. From his youth, he remembers no old men telling stories to kids "how things used to be". In fact, he knows no-one who had lived there before the war. The entire human (people, traditions, culture) and physical (buildings) history of the place got wiped away and replaced with depressing commie blocks and chauvinistic Russian settlers who are bitter that no-one treats them as liberators.
This is particularly striking considering that as a Hanseatic trading city, Narva had vibrant multiethnic population and immaculately preserved baroque architecture. It was a remarkably beautiful place that Swedes had once considered moving their capital to from Stockholm. Now it's a run-down shithole full of angry and miserable rootless Russians who don't understand where they are and why everyone dislikes them so much.
It's also notable how Baltic Russians came into existence. They were historic minority compromised of refugees who had fled religious persecution in the 17th century Russia. Some things never change.