I would love to see them gone, but politics makes it difficult. Other powerful nations would need to be on board with disbanding the UN, otherwise the USA could end up being declared a rogue nation, embargoed, economy seriously harmed, etc.

At least the USA has veto power and a significant say in global matters and also has a history of completely ignoring the UN and getting away with it.

I think they only have as much control as the US government allows them to have. The problem is when we have traitors in government who like to use obeying the UN as an excuse to do what they wanted to do anyway.