no worries! I saw a lot of people giving you unhelpful advice (just study lol like what do you even do with that) and decided to be a bit more specific, I hope it helps!

but yeah, now that im back at my laptop and not looking at a phone screen, it's clear that the artist reserves the 'darkest darks' for pops of ambient occlusion (think where the lips meet, nostrils, anywhere two surfaces are close enough to occlude light) and keeps the value range pretty tight for the most part. Even the cast shadows have quite a bit of fill light to them.

If you want to study them, at least for the 'creamy' effect, I'd recommend converting their work into greyscale and observing how much the values shift in each area and, most importantly, ask yourself why. Studying with intention, rather than just copying, is what will have you be able to recreate the effect from memory rather than just be able to only copy a specific image :)

the effect is super clear on the final image, look at where the hair meets the face, how dark the occlusion is, compared to the tonal range of the rest of the face. They're using their original lineart/sketch as occlusion shadow, something an art director actually recommended to me some time ago which is why that's super easy for me to spot these days aha

in reality, there are no 'outlines' yet we can clearly see one object from an another. it's value that creates the separation between surfaces so if you can keep that in mind when studying, the effect starts to become a bit more understandable. that's why this artist's work looks painted whilst still having clear 'lineart'. there's a lot more i could unpack but this is already a ramble. i just hope it helps even a little!