> I'm not sure the Vatican's revenue but I suppose a lot comes from the Vatican Bank and returns on their massive assets.

The "Vatican Bank" (strictly, the Institute for the Works of Religion) has pretty miniscule assets by the scale of financial institutions, and returns in the high tens of millions annually.

> Most of their charitable work comes from $2+ billion from the US Govt.

Most of the funding for Catholic Charities, a US Catholic organization structured rather specifically to be able to accept government funding to private social charities given the particular regulatory regime in the US regarding church/state relations, comes from the US government, but that organization is not the whole of the charitable work of the Catholic Church in the US, much less the world.