we believe things only once we've exhausted our attempts to disprove it
No. An appeal to authority would be "this must be true because someone authoritative said it". Saying "I am willing to treat this claim more credibly than other claims because the source is credible" is not a logical fallacy.
That's a personal heuristic - a very reasonable one, but it's still an argument from authority.
A fallacy assumes a cogent argument is being made. This is just a preference.
Whether you say "it must be true", or "it is likely to be true" does not matter. Credibility must only come from the statement itself and the evidence to support it.
However, while it is a logical fallacy, it is reasonable to temporarily hold beliefs for or against the truthfulness of a statement while no or insufficient evidence is present. As long as belief is not mistaken for proof, nothing is wrong about having such gut-feeling.
I think you are confusing deductive and inductive reasoning.
"The ad verecundiam fallacy concerns appeals to authority or expertise. Fundamentally, the fallacy involves accepting as evidence for a proposition the pronouncement of someone who is taken to be an authority but is not really an authority."
Stanford Encyclopedia of Philosophy (9):
Here we have a researcher who is an expert in the thing he's talking about. There are still absolutely reasons to be guarded-- the matter is not fully decided, it's just one study. Maybe this is an example of an ongoing controversy, and we're selectively ignoring other experts?
But it is different to extend a cautious benefit of the doubt here than it would be to take, say, Paul Rudd's word on the topic as final.
But for the rest of us, we have no choice but to trust authorities in some way when deciding how to interpret some new result.
When a person fights the establishment and shows their data and ultimately gets accepted and defines the new paradigm, they've earned a seat at the table to speculate on how things work. They proved their worthiness as an authority.
That doesn't mean we shouldn't evaluate on the merits, but the priors are very heavily in his favor.