You're forgetting, Russia's invasion is illegal. Russia's hired solders (including their own) have no right to be in Ukraine.
Putin is spending hundreds of millions into their disinformation campaign, trying to make sure you forget it was illegal.
Don't every forget. Make him waste his money.

As for those North Korean solders, well, North Korea is the largest open air prison in the world. They will never be allowed back into the hermit kingdom. Never.
So their only chance of freedom now is to get to Ukraine. If they can get there alive, they will taste freedom for the first time in their life.