C++ Make derived class instantiable only from factory / base class

I'm modelling classes to represent modules with sub-modules and so on. I make each sub-module to derive from the base class (Module).

But now I want to make it impossible to create sub-module from anywhere else than some specific method (like Factory pattern) - in order to provide some configuration for the sub-modules. See the code:

class Module
{
    public:
        template<typename T, typename... Args>
        std::shared_ptr<T> addSubModule(Args&&... args)
        {
            std::shared_ptr<T> module = std::make_shared<T>(args...);

            children.emplace_back(module);
            module->parent = this;

            return module;
        }

    protected:
        Module* parent = this;
        std::vector<std::shared_ptr<Module>> children;
};


class SomeSubModule : public Module
{
    public:
        SomeSubModule(int param1, int param2)
        {
            // ... some init
        }
};


void Usage()
{
    Module rootModule;

    rootModule.addSubModule<SomeSubModule>(1, 2);   // <-- Way 1) This is what I want
    SomeSubModule sub(1, 2);                        // <-- Way 2) This also works, but I want to prevent it
}

I want to make the "Way 1" the only way (so I can perform some init stuff in addSubModule, like add newly created module to a vector of children, init the parent pointer, etc).
The way I wrote it, the "Way 2" is still possible and I don't want it.