No

There should not be any kind of overlord above any government. Hell the government is already almost an overlord to me. I don't need more overlords.

The United Nations is an extremely effective way to keep nations like Russia, China, and North Korea from attacking and is important to keep them even if money is "wasted on military defense."

If we didn't have the UN, then it would be so much easier for countries to do terrible things to others. Plus, the goal of the UN is to create a unified front against bad things, whether those things are rogue states, or dangerous diseases.

An international body that a vast majority of world governments participate in allow for legitimate mandates that govern world politics. International recognition, for example, of sea territories sets boundaries for nations to not intrude on others. Aka China in the south-chinese sea. International conflicts can be resolved trough talking and the votes held by member nations set the precedents and allow us to determine who is right or wrong without having to resort to violence.