Also ended up with all of Europe's gold by the end of WW2, making the dollar the global reserve currency

Both facts may be true without the causal link being present.

Establishing the US as the global reserve currency had little if anything to do with where gold was stored, and far more to do with US economic and military power generally in the post-war era.

That’s incorrect. It had a lot to do with it because it represented the fact that Europe’s governments had little to no wealth after WW2 while the US had it all (thus economic and military dominance).

And wealth, as Mr. Smith says, is "the produce and labour of the nation", which is to say, economic activity, as noted in my GP comment.

True, but gold is (and especially was) a store of wealth, into which "produce and labor of the nation" had been converted over time by European nations

No, it is not.

Gold is, and has been, an exchange medium, in which national finances have been transacted, and a durable representation of wealth. It's useful in addressing balance-of-trade relations between state.

But the overwhelming wealth of states is in their internal and external production and international trade of goods and services.

Colonial-era Spain imported gold in vast quantities from the Americas, which did it little good as that didn't represent wealth but rather exchange capacity, and did little but bid up prices whilst reducing (in similar mechanisms to Dutch Disease and the Resource Curse) the real economic potential of the country (why raise grapes, cattle or other goods when you could get in on the gold exim trade instead)? Gold bankrupted Spain, ironically enough.

Britain's colonial trade focused far more on goods: spice, cotton, sugar, tea, grain, wool, lumber, saltpetre, slaves, and the like. Those are both directly useful and contribute to infrastructure. Two things Spains gold utterly failed to do.