There are a few similar topics about creating this effect. Make sure you do a little research around the forum just to see if your question hasn’t been asked: There was a question regarding creating cartoon outlines around mesh parts, this can be done by using (special mesh) and scaling it properly however a best approach would be creating an inverted mesh through blender you’ll have to export it to studio.
Here is a guide that goes into details for creating outlines on meshes which explains some of the ways to approach this. See here: