I found a couple of articles on the Internet about this question but it's still not completely clear to me.
The rule they give here is the following:
Use a form of "der/die/das" with the superlative if it is right in front of a noun. Otherwise, use "am" with the superlative.
Berlin ist die größte Stadt in Deutschland.
Berlin gefällt mir am besten.
But what about this sentence I found in the Collins Dictionary?
Wer hat am meisten Geld? ⇒ who has (the) most money?
The superlative here is right in front of the noun but we can still use am- form. Can someone explain please when this is possible?
I'm also wondering if there's any difference in meaning or usage between:
Wer hat das meiste Geld? vs. Wer hat am meisten Geld?