This is where a lot of so-called "serious" cyclists seem to lose the plot, IMHO. They obsess about "efficiency" and being able to produce the maximum power output, and spend good money on bike fits in order to achieve this. What seems to get lost in all the obsession for a few extra watts, is that riding a bike is supposed to be enjoyable, and there is nothing enjoyable about riding in a manner that forces your body into an unnatural position, like the aggressive head down arse up stance that a lot of amateurs seem to have aped from pros. The difference is the pros are being paid good money to endure the discomfort of riding like this for the extra speed, the amateur cyclist isn't.
Just like
@Drago I've been riding bikes for over 40 years on and off, and I think by now I pretty much know how high I like my saddle for easy pedalling and minimal fatigue, and how high and far away I want the handlebars to avoid numb hand or shoulder and back discomfort. Unless you have a custom-built bike, you are always going to be compromising to a certain degree starting out with whatever production frame size feels best.