The UN for the longest time has been heavily dominated by the US government. Until recently, the US power in international organizations such as the UN have been virtually uncontested for over 50 years.
Russia has been a waning power ever since Stalin’s death with its only true power remaining in its oil-production . Now it has only the 11th highest GDP meaning its economic situation has stagnated from the time they held second place for GDP size, most recently in 1990. Ever since the Soviet Union’s collapse, Russia has not been a serious threat to the US. China at the time was far from the economic powerhouse that it is today. Until 2018, China’s GDP growth was a whopping 9.5 % per year, but now China’s economic advancement has begun to slow down. China has begun to move into the next stage of development, which would be controlling the international stage to their benefit.
In the 1970’s China’s leader Deng Xiaoping had once stood before the UN, and addressed the world in a speech that criticized America’s massive spheres of influence. He claimed that this gave America too much power; yet now, Xi Jinping is following the same path Deng Xiaoping had once criticized. He began this process in October of 2017 saying that he would “take an active part in leading the reform of the global governance system,” .
Three years later and Western nations can begin to see what happened. Most recently, with the Hong Kong protests, the UN general assembly had two declarations. One was from Cuba, supporting China, & the other was from the UK, condemning the Human Rights violations during China’s response to the protests. Cuba’s support of China gained support from 53 other countries. The UK received about half…only 27. 
Even more alarming is China’s command of technology in the UN. Recently, the UN decided to partner with Tencent, a company greatly supported by the Chinese government. Tencent also returns the many favors it gets from the Chinese government by providing censorship and user data it receives from its users across China. The UN’s use of tencent’s apps is a clear demonstration that China has growing control over UN affairs. This may not seem like much, but it already caused things such as the 2019 November cyber crime, where Russia and China together pushed the US off throne of internet leadership. The 2019 resolution allows governments to shut off data from other countries under the cover of “criminal activity”, which easily can be used as a tool for oppression of political dissidents and those who speak out against the censorship, as well as other issues that both China and Russia face.
More recently, China has also begun loaning money, & providing other assistance to developing countries especially those in Africa. This has resulted in favors from the Africans that allowed Mr. Qu Dongyu to become head of the Food & Agricultural Department of the UN. Cameroon initially put forth Mr. Medi Moungui as a candidate for the position. However when China pledged two factories, worth 25 million dollars, to Cameroon, Mr. Moungui abruptly dropped out, giving China a clear path to head the Department of Food & Agriculture. 
China now heads four different departments of the UN. America, only two. China has been moving towards dominating the UN, & what they continue to do remains to be seen.
 China Expands its U.N. Clout, One Vote at a time – Wall Street Journal (Print Version)