Possible to Create Additional Viewport Modes with Addon?

So there’s an interesting CAD addon for blender that is under development and I’ve been looking to possibly help out with the project. Here’s the link if anyones interested CAD_Sketcher

Anyway, I think it would be useful to have a dedicated CAD sketching viewport mode for the addon. So the new list of modes would be like object mode, edit mode, … , sketch mode. Is it possible to add one while still being just a python addon for blender and not an entirely different branch of blender?

Not super experienced with blender scripting but I am a longtime blender user.