[UPDATED 26 January2021 ]
Once I have the lineart and base color done + a glimpse of light and shadows ideas, I merge everything, make a copy, unmerge, save all those layers in a different folder AND THEN, create a new folder for the render. In this step I work on top of everything, fixing anatomy, composition and deleting any possible lineart.
To make it short : linear and base color and lights are a guide for the final painting.
Light fixes and anatomy tuchups