... you can tune it to your personal style ...
Whenever these discussions come up, I feel compelled (and forgive me the compulsion) to point out that in
recreational kayaking everyone's proportions are different. I don't mean by a little either.
The point was driven home again watching various events at the Olympics in Tokyo. Elite athletes tend to a specific body type, that is then coached and developed to the extreme performance demands of their discipline. The end result is that the women doing the high jump have a completely different morphology than the women in track cycling (Yay Canada!). This is helpful for athletes and coaches because they know what the performance parameters are for height, weight, reach, range of motion, heartrate, VO2, etc. However, whenever you are on here, understand that some people have long torsos, short arms, bigger lungs, or some combination that may not match up with yours.
You and I have to figure out our own best performance parameters mostly on our own. You have to look at those videos as a
starting point for developing your own stroke, and actually, a set of strokes.
Bike racers change gears and you should too. You shouldn't rely on just one "perfect" forward stroke. If you're racing in the Olympics on a flat course, yeah, crank 'er in that one gear for however long the course is. By and large, that's not what we face though. There's wind, waves, and current. You need to adjust your stroke to meet changing conditions so that you can stay upright, on course, or whatever while, also moving forward. Paddle high angle, low angle, wide grip, narrow grip, loose grip -- there is likely a time for every option to be the best option for the water, for your body. Taking a one gear track bike out on the Tour de France makes no sense. Why would you lock yourself to one specific stroke out in the real world?
To sum up: (A) Figure out what works for your body. Don't slavishly follow some set, generic instruction described as 'proper technique'. Use science if available. Specific coaching if available, and qualified for your body. But in the end, it's you and your paddle. (B) Having only one gear does not make sense. Learn a variety of forward strokes that let you distribute the stress on your body and meet changing conditions on the water.
By the way, I am not arguing against any of the advice, principles, or videos above. Just pointing out that they are merely a starting place for your own explorations.