It wasn't just Stalin though, the UK and France did the same. Used captured Germans as workers even after the war ended.Are you truly suggesting Putin should send Ukrainian POWs into slave working camps and gulags like Stalin did??
Otherwise I'm again sure, we should better close this thread for good.
I personally think it is a big mistake for Russia to be accepting so many POWs in Mariupol. They already had 3x more POWs than Ukraine had and the numbers will surge even more now. Many of the soldiers are seriously wounded and will place a burden on Russia's medical system. Soon Russia will be faced with the same problem PLA had against India in 1962.
Ukrainian soldiers violated the Geneva convention by hiding behind civilians. If they are taken POW without punishment, Ukraine will know they can do the exact same with every Russian speaking city and face no consequences. The numbers of dead civilians will be hundreds of thousands and east Ukraine will be devastated.
If they've ran out of ammo, gift them a magazine and send them back into their bunker. If they are low on water, don't worry. It'll be coming soon.