This somewhat doesn’t make sense.
“Evacuation” seems to mean they were sent to Russian occupied locations. As for exchange, presumably for Russian soldiers held captive, why bother?
POWs are released after wars are over. This exchange stuff is not normal procedure.
Note that in WW II the Soviets did not release lower ranks of the German 6th Army at Stalingrad until 1949. The war was over 1945. Senior officers were not released until 1955. The most senior of those officers never returned to Germany. He lived out his life in Russia. Other officers returned to what was East Germany and most became senior pro Soviet East German govt officials.
This exchange stuff is just the latest bizarre scenario floated by . . . someone. Why would POWs be sent back to resume fighting?