There are now two classes, an abstracted parent and an inherited child.
That parent class will be exported from a head file to be a .dll file but child not be.
Assuming that we use class.cpp file to successfully generate a .dll file and
only use main.cpp file to generate a .exe file linked with this .dll file.

//class.h

#include <iostream>
using namespace std;

class __declspec(dllexport) parent
{
    virtual ~parent() = 0;
    virtual void print() = 0;

    // get a child class object to add to a child object linked list.
    // need a parent pointer to point to a child object
    static parent* getChildObj();
    
    // delete a child class object from a child object linked list
    static void delObj(parent* obj);
};

class child : public parent
{
    int otherData;
    static child* head;
    child* next;
public:
    friend parent* parent::getChildObj();
    friend void parent::delObj(parent* obj);

    inline void print() override
    {
        cout << "child: hello world";
    }
};

//class.cpp (generated a .dll file)

//this just is a roughly implementation process, 
parent* getChildObj()
{
    child* temp = new child;
    ......
    return temp;
}

void delObj(parent* obj)
{
    child* temp = child::head;
    for(; temp; temp = temp->next)
    {
        ......
        delete temp;
    }
}

//main.cpp (generated a main.exe program)

#pragma comment(lib, "___.lib")

class __declspec(dllimport) parent
{
    virtual ~parent() = 0;
    virtual void print() = 0;

    static parent* getChildObj();
    
    static void delObj(parent* obj);
};

int main()
{
    //this step is normal and able to return a pointer.
    parent* p = parent::getChildObj();

    //the vtable pointer is nullptr, generating an exception.
    p->print();
}

I want more details of how to export a class from a .dll file and how vtable pointer changed when we need to provide a library with only necessary information.
For this question,it is not necessary to have an answer. If you have a better method, thanks for your help.