Imagine how much the russian captives will wreck the russian culture. Here the general population is led to believe that Ukraine are the bad guys, and savage brutes, who kill and torture their POWs.
Then they come back, and claim to be treated better in captivity than they ever were living in russia in daily life. They get shown what western life is like. Then they come back to russia and get thrown back into daily life where the populace is exploited.
I don’t claim to know the future, but I wouldn’t be surprised if these former POWs were killed by their government for sharing truths, or alternatively, if some of these former POWs become revolutionaries in their own country seeking change for the common man. How sucsessful they are only time will tell.