i am confused on what you mean by 3d painting?
if you mean 3d printing, I would argue prusa mini or mk3s+
if you mean 3d design and you are looking for the easiest tinkercad.com, onshape.com also has free accounts
fusion360 is advanced, it allows a non commercial free version that allows some editing but not all of the advanced options and a paid commercial version.
Freecad is a standalone cad software that is, free.