note the time taken on the bonnet and the skirt
its sharp, relatively well rendered compared to lets say the thigh, I assume after roughing in, they decided those details need to stand out, because realistically, the face isn't great, the rendering on the legs is rough, the left leg I believe the curve by the ass is going in the wrong direction,
possibly some of the hair rendering could be lumped in here, but that may be a stretch.
Here is what I think happened,
they made a rough sketch/block in, more or less just lines to know where shit goes, they then went over it and made closer to final lines/the sketch, from here they took a base color for each area and just blocked everything in, then went onto background elements (including the foreground one, im including that in this step), then probably roughed in what the water was going to be/how high up it would show. knowing where the water line was, they went in on rendering it out. they then went in and did a pass on the water, then after it was more or less done, they decided to pick a few areas to really add detail, something they knew wasn't fucked so attention would be drawn away from areas that were and were not fixable without major rework. then with that done a small pass on the rest, see the 'blown out' light in the water on the upper left.
I mean if you want me to say it took 100 hours and asian genes, fine, have your fucking 'I can't possibly do this so I can just give up now' excuse, but this is how I see how long everything took.
i'm sure someone here will link the person with the latex pinup video, I have no idea what to search for to find it, then you can see how long it takes to do that slowly with traditional art, yet still be higher quality and faster then I estimated this to be.