How to know if you're asking the wrong question ?

What's that principle where you don't know you're asking the wrong question because you've got this idea in your head on how to do something, so you search frustratingly. If you could step up a level and find the right question, you'd find a well established, efficient solution.

Related to unknown unknowns I guess, but I came across a phrase or word encapsulating it, and now I can't remember or (ironically) find it.

ETA: It's the XY Problem, thanks Bophades@midwest.social.