I don’t agree with your assessment of how things will shake out. The primary concern of north and south korea fighting in ukraine (I need a new bingo card) is that the fighting could trigger N Korean attacks at the boarder, which will destabilize the region, and allow China’s neighbors to step up their military positions for legitimate cause.

China’s window to attack Taiwan was after Russia took Ukraine - now they are probably recalculating their plans and building a billion drones. That should hold for a while.

My largest concern is trump winning, and europe finding an excuse to trigger article 5, dragging us all into war, so that trump either abandons the alliance and diminishes the US world standing (or biden if he refuses to aid). European nations know ukraine isn’t the first and isn’t the last, and they might as well fight a crippled russia when the US might intercede. If the US did blink, we’d see a loss of allies and Taiwan might as well assume they’re gone in 30 years, as Europe would ignore US aid requests.

… what? Korea hasn’t existed since 1945. North Korea isn’t part of NATO, sure. But South Korea IS part of NATO.

So, I’m unclear what you mean.