i have no idea if this helps at all but i'll add you so you can look at the layers and stuff
i just kind of drew some feet and them did a thing showing each layer of shading and what color i used?
also i'm not sure what you mean by glitch thing but i tried to draw like a glitchy effect maybe? to do that make a layer on add then draw along the outline with red, then duplicate the layer move it a tiny bit and use lock alpha to make it blue then do it again with green
oh and to get the airbrush to be less you can click a bunch instead of making a line
even if this doesn't help at all it was still fun :3
if anyone has any questions about how i draw anything on any of my pictures i will try and answer as best i can