TLDR-

North Korea sends troops to Ukraine to fight/die for Russia. Tells them that if they are captured then they must commit suicide or be labeled a traitor. Some soldiers fail to properly kill themselves and are captured.

The question now is what to do with them. If they return them to NK then they will probably be tortured and executed, if they grant them asylum in Ukraine or South Korea then NK may use that as an excuse to increase hostility. Geneva convention requires that they return them to NK.

Send them back to NK. Send them the first leg of the trip on a bus driven by a single unarmed soldier. If the North Koreans somehow manage to overpower the driver and commandeer the bus, and drive it to wherever they please... "Well, shucks, guys, we did what we could."

However, if there is credible risk of torture or persecution, repatriation against a prisoner’s will is prohibited.

That would be a nasty oversight, but it doesn't actually appear to be the case.

I wish there was a way to efficiently spread knowledge inside NK that if soldiers surrender, they will be allowed to return to SK or NK according to their own wish. That would at the same time dramatically increase North Koreans' willingness to help the Russia in the war, and just as dramatically reduce the North-Korean leadership's motivation to send any soldiers to that war.

Anyone from NK can get South Korean citizenship, you just need to convince the authorities you are actually from NK

speaking Korean and being captured in Ukraine should narrow down the possible nationalities quite a bit

If that's in the Geneva Convention, it would be against it to return then to NK. Let SK talk to them first.

Yeah, this article feels like it's trying to imply a tension that doesn't exist. Ukraine has no motive to send them back to NK, there isn't a legal basis for it, and nobody in here actually says it's being considered.