I found this answer to our topic “Finger Dexterity” a truly invaluable piece of advice and perspective.
It definitely worths being read… Juan Rezzuto
Focusing on dexterity is somewhat like a student trumpet player who only wants to play high notes.
Yes, you have to learn them someday, but they are a tiny part of the skill set and not the part that limits a beginner or intermediate.
For the beginner, keyboard geography and coordination are the hard parts on piano. It will be years before they have a challenge in dexterity. They will work on it along the way, but it won't be an impediment until they get into advanced literature.
And even that position can still somewhat be considered lip-service to traditionalists, who don't want to actually think things through. The nature of the instrument and how we interact with is actually ballistic, which implies a completely different sort of conception of what we have to do.
For example, if you are in the habit of practising a segment of notes, and end articulating a note without it being sent on top of the next (at the perfect spot and height so you have full control of leverage), you are practising the entirely wrong timing.
There's also fundamentally a difference between the speed and timing of what happens between notes (essentially the horizontal plane on the keyboard but also the 3-dimensional rhythm of the body) and the speed of the articulation of the note (the vertical dimension or pressing of the note).
Which plane/dimensions involves more "space"? Which requires more motion that has to be refined? The answer to those questions will tell you what ultimately limits us. This component of the coordination involves far more degrees of freedom that has to be "solved/optimized":
There is indeed an interaction between the two, but the precise interaction can't be figured out until you actually can feel the difference and know the timing involved.
The real problem, later on, is precision and perfect timing that keeps you going forward but "spaced" out such that the fingers always have support, no exceptions.
On a related note, but slightly different tangent....
The timing behind this is also related to errors in musical timing as it can be mapped to physical coordination. The common clapping tool for rhythm can elude students from the correct sensation of timing because it focuses on the articulation and not the spaces in-between. (You can do it and sense it correctly, but the people who naturally do it, rarely have problems with rhythm in the first place).
Walking is slightly better, but mostly because it's far easier to feel the difference between the correct and wrong ways of doing it. The incorrect way primarily senses the sensation of how the feet hit the floor without any regard for what happens between. It should feel more stagnant and can have the sensation of being behind, losing momentum, and having to catch up. Imagine a hill between two valleys. The sense of articulation feels like a boulder from the first valley that falls back down to the valley and can't climb up the hill on it's destination to the next.
The correct way can also feel the articulation with the floor but it connects it to the follow-through in-between such that you feel that you actually have full control of spacing things out. It also has you feel how the body smoothly interacts with gravity at all times during the cycle, whereas in the other way you are not likely to feel it at all.