I get it but in this context "authority" means an authority on a particular topic, not like a police officer or something. Appeal to authority becomes a fallacy when you appeal to someone who is not actually an authority on the subject at hand.

It's also when you have no argument and when confronted defer to "they must know their shit"

But how do you determine if someone is an authority? Our world is filled with epistemological bubbles. One person's expert is another's snake oil peddler.

Right, I don't think we really disagree about anything. "That's an appeal to authority" is not a useful objection, because appealing to authority is often a great idea. "That's not a good authority" is a good objection and often very relevant.

It's sort of like seeing a lot of arguments that rely on false or misleading evidence and deciding that "appeal to evidence" is a fallacy. The choice of authority or evidence is the issue, not the act of appealing.