The same place it’ll be now: Unable to substantively act because by design the five veto powers effectively neutered the ability of the UN to act against them.
The US is just one of the five, the UK, France, Russia, and China are the others.
Why do you think no UN action was taken against Russia for annexing Crimea and invading parts of Ukraine in 2014? Or against China for its treatment of the Uyghurs?
None of this means the US ‘controls’ the UN though, any more than the other four veto powers do.