Hi Death,

to make your objects paintable in Substance Painter and to make use of all advanced options you will need to unwrap all your objects and assign uv maps to them. There is no way around this. You can do this in a program like Blender (free) which has a good tool set or use specialized software like RizomUV for this. Whatever way you go, unwrapping is a must and comes with a learning curve. On top of this you might have to deal with retopologizing your models depending on your later use case.

Regards,
Sven