Of course there was collaboration with the Nazis in the beginning. If you go to the Shoah(Holocaust) museum in Vilnius, you will know that the Nazis hid their plans for the Jews by employing local Tatars to do the work for the first 2 years. That all these people had been under brutal occupation by the Soviet communists for 20 years, lost their property rights and had family members disappear. Damn straight you would think this new army coming in were liberators. As for Ukraine, a place starved by Stalin, history is more nuanced with people like Banderas assisting them yet also foiling their plans to target Jews and finally being imprisoned by the Nazis.

You can visit the museum of occupation in Riga which includes both the communist and Nazi periods. You can read how Frunze crushed the pan-Turkic republic of Turkestan by visiting Uzbekistan, or visit Georgia and learn about the republic of Georgia ‘s brief democracy after escaping imperi Russia’s yoke, only to be crushed under the Red Army.

Btw collective punishment and ethnic cleansing is never a good or justifiable thing, just because some people collaborated amongst those populations.