Basically Python isn't installed. I'm not sure if I'd want to install it tbf (my system is already cluttered with ton of stuff and I'm not sure if I ever will want to move from C to python).
Starting 3D Paint (no-cache server)... Python was not found; run without arguments to install from the Microsoft Store, or disable this shortcut from Settings > Apps > Advanced app settings > App execution aliases. Press any key to continue . . .