Many ethnic Germans fought in the Wehrmacht, my own Grandfathers among them. Did the Red Army also conscript people with german ancestry or were they too distrustful of them?
Short answer: yes. There are accounts of Germans fighting the Nazis in Red Army uniforms in several battles including the Defense of Brest in 1940. (https://www.norkarussia.info/uploads/3/7/7/9/37792067/deportation_and_destruction_soviet_germans.pdf)
Long answer: Not usually. The NKVD officially banned ethnic Germans from serving in the Red Army, and instead forced them to serve in “labor columns”. However, in some cases when the Soviet manpower situation was dire, they made exceptions and would particularly overlook German ethnicity when the recruit was considered “Russified.”