This is a good question. I would offer that there are at least two major types of soy sauce: light and dark. They are used in a variety of ways in Northeast Asian cooking (Mainland China, Koreas, Japan, Taiwan, Hongkong, Macao). For example, when you steam a fish (southern Chinese/Canto style), you use a combination of light and dark soy sauces. (I have no idea why, but this is a traditional recipe taught to me years ago.) Soy sauce has two primary "taste" components (previously I discussed visual components): (a) the fermented soy beans and (b) the umami (MSG/monosodium glutamate). Even if you feel like (a) is overwhelmed by your cooking, it is still enhanced by (b) which, for most people, makes any savory food taste more appealing.

For me, nothing beats raw fish (sashimi or sushi) as a taste test for a soy sauce, but I frequently use a mixture with Japanese ponzu... so ignore any expertise that I have on the matter! I am sure that each culinary region in Northeast Asia will have a different answer. You could probably interview 100 chefs from the region and get 25 different answers.

Lastly, there is a third type of soy sauce used in Southeast Asia called sweet soy sauce, or kecap manis in Bahasa Melayu/Indonesia.

Surely, "salt" has to be mentioned when talking about the primary taste components of soy? Normal soy is around 17% salt, which is a lot and really plays a part, in my opinion.

Kecap manis is delicious, I get the ABC brand. It's as thick as molasses. Wonderful drizzled over some chicken rice

Oh, sweet soy sauce is a thing in Asia? I thought it was a French invention (all restaurants here give you both savory and sweet soy sauce).

Also I just had gyozas with Lee Kum Kee light soy sauce and thought it's a good test for it.