The lines are not good. The smoothness that comes afterwards is also weird. Too big a contrast. The texture on her ass is also low resolution. A lot of problems. I imagine that editing the textures in photoshop is what L&P is doing. Maybe he also is trying to increase the resolution. Unfortunately this cannot be done by AI properly. Another way to do it is kind of merge the texture from real life photographs with the existing texture to add real life details. All of it is hard and time consuming work. A profession might do it faster but I am far from that and I think while L&P has some knowledge of Photoshop he is also not so good at this part. Hence the long time to do it.Don't you like the wrinkles from the curves on her pelvis to her legs?
If so use photoshop!
LP uses face app or AI on new renders, what is the problem fix this?
Moreover, this is not the most noticeable area! Well, or open it in the editor and edit it in Photoshop, then place it in folder of the original texture, what's the problem?
Also, what makes you think L&P is using AI on the new renders? (Not saying he isn't, it's just I don't know what makes you say that)