Is this something you encounter more in discussing research or philosophical problems, as opposed to personal situations?

I see things like this pretty often:

A: I'm really stressed out today. Everything's going wrong! My boss called me lazy, my car started making this funny smell, every time I try to use my phone this stupid error comes up that says "Invalid Transit Proxy", and my cat is sick and it crapped all over the floor.

B: Oh, "Invalid Transit Proxy" means you've set a custom pipeline server for outbound sessions, and it doesn't ping. All you need to do is go into Settings and reset it to the factory network configuration, so it can DHCP to your WLAN and ....

A: Dammit, I don't want to try to fix my phone right now! I have to clean up all this cat mess; the smell is making my eyes water.

B: Dude, don't bite my head off, I was just trying to help you be less stressed.

Or are you thinking more of situations like this?

C: I read this interesting Wikipedia article this morning, on philosophy of suicide. Camus asks, if God doesn't exist, why we shouldn't just commit suicide. I'm not sure I buy his answer though, because ...

D: OMG DON'T KILL YOURSELF! (calls suicide hotline)

In the first scenario, B doesn't know how to deal with A's overarching problem (being stressed out), and responds to just the one thing B does know about (technical trouble) which doesn't happen to even be the most immediate stressor (cat mess). If B had offered to clean up the cat mess, A probably would have appreciated it.

In the second scenario, D pattern-matches C's topic of conversation (philosophy of suicide) onto something they think they know how to respond to (suicidal ideation) and responds on the wrong meta-level. D can get this entirely wrong: C may actually think, "I observe that I am not suicidal, but some people are," and D misreading C as saying, "I am suicidal."

I reckon the term "mansplaining" is often directed at this sort of behaviour, but for various reasons don't want to co-opt it for this purpose.

Wise decision.

I am fairly certain mansplaining refers to when a person in a position of privilege "explains" to the unprivileged individual "facts" on certain topics that they, as they are in a position of privilege, are uniquely unqualified to explain. Specifically sex privilege. Cissplaining, straightsplaining, and whitesplaining have more of this sense than the following sense: When a male explains to a female (usually condescendingly) something that they assume the female (usually knowing this thing) doesn't know (usually because they are female).

I don't know how that fits with your proposed instance of hypodiction. Unless ME knows how to solve Problem Z and their knowledge is specifically related to the concept.

But yes, that should be a word.

In what context would you actually use XXXXX? My response to that may be something like "The problem you've solved is not the problem I have."

(Half-joking suggestion: the word should be "to shoelace", because "XXXXX" resembles a shoelace.)

Dude you just strawmanned me. They defeated a weak/the weakest sub-problem.

I usually use “Z was just AN EXAMPLE!!! Grrr!”

On further thought, I think "geeksplaining" may be an excellent word for this cluster of behaviours, and I may even start using it.

Edit: e.g. my blog got Redditdotted yesterday. Geeksplaining advice "switch to nginx!" No, that doesn't actually work with the stuff I've already said I'm using, you just said it because it's trendy so it occurred to you to say it. Applicable when people say something that's helpy rather than helpful. I foresee this being a vastly useful term.

Pattern-matching?

Not sure "splain" is the precise right word here - it covers the tone, but not the selection of which bit to answer - but I know the behaviour you mean. It's part of why asking a question of my geekosphere requires predicting and heading off said behaviour in advance. It's one of the least offensive of the cluster of obnoxious geek behaviours I think of as "Slashdot-style argumentation".