It’s always been both, just with our current problems offloaded to aliens for scrutinization. That they’re no longer using aliens for commentary is the problem.
That’s not new. Turbolifts on the Discovery were depicted that way pre-refit, back in the TOS-ish era. It’s a (mind-boggling) stylistic choice or something.
and they certainly treated specific items as “valuable” (historical items, weapons, and especially liquor.)
Historical items definitely have non-monetary value. They can’t truly be replaced since, no matter how accurate the replica, only the one chair will be the Enterprise-A’s captain’s chair, for example. Replicators have software restrictions on what you can make with them, so you can’t just replicate weapons under normal circumstances, which creates scarcity and gives them value. Starfleet replicators also seem to be restricted from creating alcohol, which means most of the characters we see can only get it on shore leave, which also creates scarcity and therefor value. Alcohol is probably significantly less scarce when sourced through civilian replicators. The ones on DS9 are programmed with Starfleet’s restrictions, though.
DS9 is a Bajoran station, not a Federation one. The Bajoran economy is not post-scarcity and still runs on money. Either Starfleet officers get a stipend to purchase things when posted on such assignments, or Quark simply bills Starfleet. Either way, Starfleet/the UFP likely has a reserve of latinum and other resources for trade with other nations.
If it was mentioned, it was probably in ENT. They talked a lot more about grav plating in that show than any of the others, probably more than all of them combined.