How does comma placement work when there are multiple instances in the same sent...

Lately, I've been researching grammar a lot to gain a further understanding, but I have come across something that's been confusing me for a few days now. I started learning about the respective adjective categories—number/quantity, opinion/quality, size, age, shape, color, origin, material, and purpose. They made perfect sense to me in the beginning, and I understand how commas work for sentences that exclusively have either cumulative or coordinate adjectives, but when I tried to learn about listing a multitude of adjectives in one sentence—some coordinate, some cumulative—I started to get confused because I came across different answers about how to go about doing that and placing the commas correctly. Their diverse reasoning behind their answers confused me even further. Now I'm just perplexed because I don't know which answer is correct, and I don't want to rely on my instincts, either. I really just need a definitive answer that will ease my doubts.

So for example, with this sentence describing someone's hair, should it be

1. beautiful, silky, healthy, long ringleted, wavy brown hair
2. beautiful, silky, healthy, long, ringleted, wavy brown hair
3. beautiful, silky, healthy, long, ringleted, wavy, brown hair

These are three ways that I remember seeing different sources claim you're supposed to place the commas. Personally, the second version feels right, but I'm unsure. What's the proper way to do it and why? Please, if you can give me a reliable answer to these questions, I'd really appreciate it if you could help me understand this better.

While there are some exceptions, the general rule is that you put a comma between each adjectival phrase that modifies the final object. These are called "coordinate adjectives". See for example missing commas between coordinate adjectives?.

Some of these phrases may consist of multiple words, and in this case you don't put commas between those words. In your example, this may be the case for "long ringleted" -- if "long" describes the ringlets, you do not put a comma between those words (you might hyphenate it as "long-ringleted"). But if "long" describes the hair, you should put a comma after it.

You should have a comma between "wavy" and "brown" because wavy cannot describe brownness. These adjectives clearly both apply to the hair.

We often don't bother with commas for very short lists of coordinate adjectives, especially just two. So when we want to say that the hair is wavy and brown, we may just say "wavy brown hair" rather than "wavy, brown hair".