I am really curious about this topic that is being discussed here: How does one learn a stroke?
I imagine what is being said is not "just imagine the stroke and stop thinking about mechanics even in practice (or even in shadow strokes)" but more like "start simple and focusing only on one thing at a time, and keep repeating, then add another edit to your technique step by step")?
Or am i getting it wrong? I know nothing about body mechanics theories/etc and am really curious about how to best learn/correct one`s form. [I am also aware there is no consensus on "perfect right form" and that one might see e.g. TiLong`s great video on BH Topspin against Backspin but he does not address how one needs to adapt ones`s stroke to short (slow, med, fast ball) vs medium long vs long (for all these one could factor in low, med, high height balls too). Like watching FZD match, his backhand stroke can look really off depending on the incoming ball but that is not "wrong" form, though there is a somewhat ideal "if you have time/space/energy" form (which is shown by many tips videos like TiLongs).
Appreciate the knowledge/etc.
Learning theory is a broad topic, so let me give you a very incomplete skeleton of an answer.
So I, like you and many others, worked with a variety of coaches over the years. The two most influential coaches were one at the amateur level who taught me a lot about how to hit the ball without really moving, and another at the national/international level who taught me a lot about how to generate good racket head speed by applying whip mechanics to a variety of strokes. Over time, he also began to get more technical about how to use the body to drive the upper arm and by proxy the racket through various paths and I am sure the Chinese are even more specific and technical in their advice. That said, there is also a lot of human learning theory tied to this that is important for learning anything. Mirroring people as children and adults is a huge part of things. Engaging the right muscles in exercises especially as a child is also critical as learning anything has neuro-linguistic aspects. Then there is the concept of adaptation.
One of the things that made a big impression on me was when the international coach and a mutual friend were working online together and he had the mutual friend learn to loop backspin without an instruction on how to loop backspin other than learning a backhand topspin in general. Over a period of about 15 to 20 minutes, the mutual friend learned to play topspins against backspin balls and adapted his stroke plane to the ball over time. He then proceeded to loop topspin balls off the table. So the international coach stressed that it was important to challenge people with adaptation so that they could develop the ability to adapt to different spins etc.
So very often, if I am teach a stroke, I have a broad template for the swing. Usually, as long as one good player does something similar or it checks a few boxes, I am good. The biggest thing I look for is swinging towards the ball. Both on blocks and on loops - making good contact. Many players try to spin so much they end up whiffing the ball or become inconsistent because they are not swinging towards the ball. Then I look for some sign of body usage and whip mechanics with limited use of the upper arm. All that said, if someone is playing at a high level with their swing because they are just good at reading the ball and the game, it is what it is, no point in wasting too much time with discussing other things.
Once the swing is reasonable, the rest for me is adaptation. Play against topspin, play against backspin, play against no spin, play against sidespin, play against pips and learn to adapt the stroke to more and more circumstances.
The amateur coach was very big on plays because he had a basketball background. So he would train his students on thirdball or serve return or to serve long and counter or serve long and block or a lot of things to improve specific sequences that were costing or winning points. He was an amazing backhand coach, his pride point was that he should never have a student with a bad backhand and as far as I know he was very successful. So he helped his students play faster and better by defining how they would play. That was partly how my backhand oriented blocking game developed at the time, it was much later working with the international coach that I developed footwork and forehand, though then my knees went away and it became a waste of time to train too much (but I am stubborn)...
In reality, what limits most players is first and foremost speed of play and ability to adapt given speed of play. Of course, spin, power, footwork etc. all affect speed of play and ability to adapt. But if you read the game well, you can always compensate with anticipation and touch. All those other things that are more easily teachable just allow you to compensate for not reading the game perfectly.
But what I did because of adaptation - I just try to incorporate a lot of different balls in my practice. I try to practice against backspin, topspin and no spin and various sidespins. When I loop to block, I always consciously vary the speed and vary looping distance so I am not locked into one speed or one tension. I try to play against opponents who are allowed to vary stuff to some degree so I can learn to adapt (but I am not healthy or fast enough anymore to allow infinite variation, but there has to be some or you will not grow). But of course, all this assumes that you have a good reasonable swing that you are okay with. Then you can practice adapting it.