I agree that democratic socialism is probably the closest IRL system, I just think it's fairly vague about it and any assertions are easily glossed over or disregarded as fiction, or attributed to the advanced tech.

It comes back to the disconnection of tech, the vagueness, the allegory. You don't see queer people, you just see allegories for queer people that are either safer to accept or just aren't acknowledged as allegories. You don't see Federation imperialism being questioned that much, they're pretty much always right. The only meaningful people who question it are the Maquis, and Sisko loses himself in his vengeance and pursuit of them (but is never humbled for it—from the audience's perspective, he's right). And then there's S31, which is fascist to begin with.

And I'm just talking about canon here. Not the books or anything like that.

Technically money was abolished prior to the invention of the replicator, but we never hear any details about that. The most detail we get is a one off line in Voyager about a "New World Economy".

They don't flesh out what the economy actually looks like, or how we got here without replicators. The "without replicators" is an important bit, which might seem like a random thing for me to be focusing on but I've talked to conservative fans who will often cite replicators as something that would be required for the Federation's socialism. Even liberal fans often think that. The message of the show is about post-scarcity, not workers owning the means of production. It's not socialism in the ways that it exists on earth, and so conservatives don't hate it.