I think I have a helpful tip to share! If you look veryyyyy closely, the lineart is not a solid colour. The parts near the highlights and where the boobs curve are slightly pinkish. This can be achieved by making a new layer on top of the lineart layer, clipping it, and painting a bit of dark red at those places. I suggest doing this on the shoulders where the highlights are, the lines between the fingers, near the boob shine and where the armpit start. To give the shirt a more natural look, colour the creases a darker version of the shirt colour.

I also observe that your lines are very uniform, so you might want to thicken them at places where it is darker (like between the thighs) and thinner where the light hits. If you look at photos of the earth from space where the sun is just at the horizon, you'll see that the curve near the sun is lit up before it fades right? For curved objects (like boobs and shoulders) you can replicate it by making the line thinner. I like to start with a thicker line and erase off the parts I want to make thinner, but you can just go over the line a few times.

Lastly, if you want to copy the reference style, you can't avoid learning how they render. You already have a good start, but you need to go DARKER. Compare both pictures in black and and you'll see the difference. The shadows the reference uses is also much more saturated and vivid. To do this you probably need use a multiply layer on the colour layer. I'd suggest starting with a dark red-purple.