Courage of convictions.
Google it, It makes perfect sense. It's using expertise in an apparently closely related field and using your valid expertise in that related field to claim expertise slightly outside your field.
No it isn't - see later below - you may not possess the required tools to be able to include yourself in a valid or credible discussion, and at some point you really need to accept that experts hold the answers in their fields of expertise.
If we're discussing Fallacious Arguments, then I'm going to drop on you that proposing that you cannot trust any expert because some may be bad actors, then this is a Sweeping Generalisation Fallacy.
I didn't say that. I said that disagreeing with an expert, (indeed, disagreeing with all experts from what you said above) without having the necessary expertise to do so is immature.
If you go through life believing that all experts are to not be trusted, on account that you believe that some of them are being untruthful some of the time, and therefore requiring of them that they provide proof to you at every juncture, that is a bizarre way to approach experts in particular and life in general, imho. ymmv, but I'm suggesting that you might be asking for too much, all of the time.
Philosophical discussion - how would you propose to "seek the truth" without "proving AND disproving" the appropriate material questions?
Second sentence - about showing that proof to all - this is what Peer Review research does. Why do you propose that this method is distinctly named as "PEER review", rather than "layman review". Doesn't that title of PEER review back up what I've been saying all along? And doesn't it bring into question whether experts must ALWAYS provide you, as a layman, their workings, as you have been insisting? Peer review has a reasoning behind it - in that it allows those people who possess the required equipment to contribute towards the output of the research endeavour - in whatever that field might be - it is there specifically and purposefully to provide counterargument. It isn't there to gather consensus - it aims to uncover whether the research can be criticised - and to take on board criticisms and go back to square one. Which begs the question about established scientific consensus (see below) - whether a layman always must be provided with proof - and the basis of scientific consensus being above the challenge of "Argument from Authority"
Fallacious Argument:
Several resources exist which describe and explain Argument from Authority or Appeal to Authority Fallacious Arguments;
Excerpts:
" an appeal to the testimony of an authority outside of the authority's special field ..."
"It's important to note that this fallacy should not be used to dismiss the claims of experts, or scientific consensus. Appeals to authority are not valid arguments, but nor is it reasonable to disregard the claims of experts who have a demonstrated depth of knowledge unless one has a similar level of understanding and/or access to empirical evidence."
It is also extremely important to note that an expert will almost always use a technical lexicon within their field that layman do not have the tools or understanding to decipher. Oftentimes the concepts being discussed do not lend themselves to non-technical speak, and putting them into layman's english loses meaning or context.
As a simple example, in discussing GPS satellite orbits, the term sidereal day is required to be used. GPS satellites have a re-visit time of exactly twice per day on their inclined orbit, yet they orbit the earth once in 11hrs58min. A layman might notice that 2 x 11hrs58min is not "exactly 1 day" and argue they have found fault.
Laymen are most often not equipped to discuss within expert jargons and this is the genuine reason that Argument from Authority is not a real claim against an expert within their field of expertise.
Another important point for you to note is that you are not really free to debate my solutions to triple partial differential equations in my calculation of aerodynamic phenomena even if I don't provide my workings, if you have no expertise in solving triple partial differential equations yourself. So when an expert says that X = True, and you want to dispute that, it is not for the expert to instruct you into developing the skills to solve triple partial differential equations. The layman needs to do that for themselves if they wish to dispute or, alternatively, put up and shut up. This is not Argument from Authority Fallacy. And you can't just wave your hand and say "I don't believe you, therefore I'm claiming Argument from Authority as my credible counterargument". That's just deliberately deceitful - and rendering yourself, at all times, just as bad versus on the rare occasion that you encounter an expert who is being a bad actor.