The United Nations organisation shouldn’t be understood as a neutral entity, and the fact that one of its core founders, benefactors and yes, historical funders is so brazenly rejecting it is just another signal that they have less and less interest in the facade of diplomacy.

It’s hard to say to what degree it might be replaced or salvaged (e.g. if the US elect a Democrat government), as it’s inherently used to hostile nations. I don’t believe it will be replaced through a split - the whole concept is that it’s a global organisation, not a bloc.