No.
NB: this does not necessarily refer to a one world government; indeed it could be as basic as simply becoming a sexed up and more representative version of the General Assembly.
Even that is a step forward to a one world government.
A one world government would be am improvement on the current world of shadowy, fragmented elites that hide their wealth across the globe and use the divisions of nation states against us.
It could mean we could push for some universal laws for working standards, environmental standards and human rights. We could use such a place to mediate peace, meaning the nations of the world could start to dismantle their huge militaries and, most crucially, the intelligence agencies; reinvesting the peace dividend in tangible stuff like healthcare and education. You could form a coordinated tax policy that means the old worries of capital flight will effectively be irrelevant.
Tbh I think the mad old war criminal Trotsky was right about one thing - socialism (or really any approach that prioritises human dignity above subservience and rat races) is impossible in a world married to the nation state model.
The good thing about dictatorships is that there are always places to flee to.
If some crazy general staged a coup under a one-world government, you're screwed.