For Russia, sure they had noone to invade. As for the USA during Trump years, what were the talks about Ukraine about? Not forgetting that Crimea had been annexed and illegal occupation was ongoing. The Russkies had time to prepare because apart from Hunter Biden, interest in Ukraine from the US side was nothing. Not sure any military assistance was provided in order not to upset Putin.
As for North Korea, when the USA cancels military exercises with South Korea and in October 2020 the Norks roll out the monster missile they finished designing.
www.armscontrolwonk.com
That being said, having talks was a good idea, always better to talk than to insult foreign leaders on twitter.