No, it's not about the "optimal way", it's about the oft-cited the factoid "90% of people are haptic learners, 30% are visual learners, 15% are auditory learners, 25% are text-based learners". Somebody did an experiment and found out 90% of subjects remembered something later when they had to learn to do it, but only 25% remembered when they had to read it. (All numbers made up, does not matter in the context of this comment)

Of course, this completely misrepresents the experiment! After learning to do something, you are 90% likely to retain it for a certain duration, after you read about it, you are only 25% likely to retain it, so in aggregate you only retain 25% of what you read.

The idea was never to find people who are "visual learning type" or the "non-learning-by-doing type".

That's what became of this idea in education through the game of telephone that mangles experimental results on their way from developmental psychology and cognitive science into education departments, and then into future high school teachers during undergrad lectures. Even my own high school teachers in Germany talked about learning types as if there was such a thing.

Sorry if I was unclear. There is no singular optimal way of teaching. But for every subject, there is an optimal way to teach it. And usually that optimal way is a combination of visuals, auditory, reading, etc.

Way too often, someone achieves understanding when information happens to be presented in an optimal way for that information and they instead believe that the way was optimized for them rather than for the information.

Then they get stuck on "I need to watch videos to truly understand it".