Sketch AI: Transforming Stick Figures with AI Magic

Perhaps such a tool already exists, but I've been unable to locate it. I'm interested in a tool that allows me to sketch my rudimentary stick figures and basic objects on a screen, with AI then refining them into higher-quality images. For instance, a user might access a QR code, which would prompt an action on a website. However, I prefer drawing these elements rather than selecting icons or using a conventional website mockup tool.

I want the style to be VERY simple, with no flashy gimmicky stuff, just simple diagrams.