I use this flat brush only for most of my ipad paintings. Then I blend some (more or less) edges with the smudge brush which adds texture too.
In the cover image you can see at the right 0% use of the smudge tool, at the middle 20% and then I added a layer of brightness just with the flat brush.
At the left I smudged it more and I added brightness on top too but less because I wanted a matte look.
I use an IPad Pro M1 (11 inches)