"I've read a number" from where? Sources? Such "easy" discussions cannot be done easily. And highly specific answers to some questions cannot be obtained. Part of the problem stems from Soviet secrecy which is still in effect. The other problem is the introduction of bias into some scholarly works. It should always be removed. It is not history. The author of any book or article cannot be allowed this. IF the Soviets maintained records of ALL German POWs, they are unavailable to researchers.
The following may be helpful. At the least, it provides the necessary perspective:
https://jordanrussiacenter.org/blog/...e-soviet-union