

Russian state media. Not a credible source for anything (see also the other articles for some glaring examples of misinformation).
Although if Ukraine has less PoWs to exchange, part of the reason might be that Russia would rather see their soldiers die than surrender. They actively shoot their own soldiers.
There’s tons:
https://www.bbc.com/news/world-europe-67234144
https://www.newsweek.com/video-shows-russian-military-shooting-own-retreating-troops-ukraine-media-1806118
https://www.dailymail.co.uk/news/article-13891677/Deserting-Russians-killed-snipers-wounded-troops-no-longer-evacuated-injuring-avoid-fighting-intercepted-messages-reveal.html
https://www.kyivpost.com/post/18201
https://united24media.com/latest-news/drone-footage-exposes-russian-soldiers-killing-their-own-wounded-on-the-battlefield-10164
https://kyivindependent.com/intercepted-calls-suggest-a-russian-commander-ordering-to-shoot-ones-own/
https://www.businessinsider.com/russia-opened-fire-on-own-surrendering-soldiers-with-artillery-ukraine-2023-9