OK I should know this but I haven’t used texture painting in Blender ever. Thought I would give it a try. First layer painting no issue. But then I need to add another layer to get the effect I want like you do in Gimp or Photo shop; can’t find it. Can you not texture in layers in Texture Paint and then blend them and change opacity?
Jeez! Back to Gimp for me.
There’s a free add-on that implements texture layers in a more traditional way: