I appreciate that you and [MENTION=97077]iserith[/MENTION] regard this stuff as highly contextual - I think you're right to do so.The beauty of the goal/approach method is that I don’t need to have a bunch of specific examples memorized for what would or wouldn’t constitute what kind of check at what DC. I can evaluate that at the table, with the full and appropriate context, based on the player’s stated goal and approach. So, I don’t have an example of an approach for you off the top of my head. Give me an example and I’ll tell you how I would rule on it.
But I was still curious about examples. Partly because I'm having a hard time imagining any myself that would fit within the constraints you've established.
In the real world, the way that people use their musculature to jump far is by limbering up their muscles, taking a measured run up and giving it all they've got. Particularly outside the context of a professional athlete on specially prepared surfaces, this can produce variable results depending on placement at the time of launch, vagaries of terrain at the launch point, whether they notice a jaybird sitting on a tree branch as they're about to take off, etc.
But you seem to have ruled that out, on the grounds that the rules on p 64 already take all that into account. Which is why I'm having trouble seeing where you see the scope for the rules on p 59 to do their job - that is, for it to (i) uncertain whether someone can clear a distance by jumping, and (ii) for the resolution of that uncertainty to depend on how well they deployed their muscles and physical training (which in mechanical terms is a STR (Athletics) check).
Likewise iserith seems to have ruled it out in saying that "I jump" is not an approach to solving the task of clearing a chasm. (Or, at least, not an approach that is uncertain in its outcome, because p 64 mandates that the results of such an approach is either certain success or certain failure.)
And for clarity: this curiosity on my part is quite independent of any bigger issue about ways of RPGing and when to engage the mechanics. It's framed entirely within the approach to action declaration and resolution that you and [MENTION=97077]iserith[/MENTION] are advocating, which - as I've said - I agree is how 5e seems intended to be played. My puzzlement is entirely about your reading of p 59 in light of your reading of p 64.