Plane probably had all the POW’s that Russia had already tortured & killed, this way they can get rid of the bodies in a staged plane crash, and blame Ukraine in the process!
You’re not even remotely realistic.
Russia and Ukraine have been exchanging prisoners all along. There have been MANY such exchanges.
Russia is actually making it easy for Ukrainians to surrender, and many do. There have been company sized units that have surrendered.
They are fed, housed, medically provided for and notification of capture is sent out.
Even mercenaries, to include US citizens which could technically be hanged, the Russians are holding onto (trial then prison).
The plane has a value, the pilot and aircrew have a value and are Russian... Probability of your theory being true <.1%