I suppose the presence of a premodifier might be relevant to the use of determiners in some cases, but I don't see any general pattern along the lines of the one that you are suggesting. It is certainly possible for an uncountable noun to come after one or more premodifiers, but no determiner. In fact, many common phrases are of this form: "hot water", "cold water", "whole milk", "good advice", "wet sand". (Uncountable noun phrases like this can be used without a determiner either in generic or in specific contexts: e.g. "Good advice is valuable", "Cold water is a common beverage" or "Alex gave you good advice that will help you solve your problem", "I splashed cold water on my hands." For the second pair of sentences here, the non-count indefinite determiner "some" could be used, although it is optional: "Alex gave you some good advice that will help you solve your problem", "I splashed some cold water on my hands.")
"A wealth of X", with the indefinite article, is just an idiom that can be used whether or not "wealth" takes a premodifier: "George Curzon, for example, possessed a wealth of governmental and administrative experience" (Stewards of the Nation's Art: Contested Cultural Authority, 1890-1939, by Andrea Geddes Poole, 2010; p. 70).
The word "wealth" can be used with a premodifier and no determiner: "a person of great wealth", "They possess great wealth".
As Laurel mentions in a comment, many words have both uncountable and countable uses.