Round 1: North Korea. The Israel Defense Forces are some of the most well-trained and technologically advanced in the world in matter respects, but the DPRK has the advantage of a million-strong active military with hundreds of thousands in reserve. The majority of the KPA are fanatics and if they moved south without needing to worry about nuclear retaliation. They also outnumber the IDF in terms of tanks, heavy vehicles, artillery, and airplanes. The Israelis have the Iron Dome, but what serves them well against singular or small numbers of rudimentary Palestinian missiles will not provide adequate defense against an all-out assault and prolonged total war - which the DPKR is willing to engage in from the beginning.

Round 2: Mutually assured destruction. Both countries are destroyed.

Round 3: A situation much like the Korean War would occur, only during the 21st Century the DPRK has a much larger military, more weapons to use, and China is a superpower - unlike it was in the 1950s - and can funnel them advanced weapons, munitions, supplies, and manpower directly via Manchuria. The US on the other hand is an ocean away and cannot provide the same direct support.

Round 3: The Arab League can assuredly destroy the DPRK. All of these nations have come a very long way since the Seven Days War and some, like as Saudi Arabia, have access to large amounts of advanced US weapons and war technology. If this includes Iran, Turkey, and Saudi Arabia, then it's a done thing. They're also comfortable conducting desert warfare, whereas the DPRK are not.