C++ 添加 2 个 3D 矢量返回垃圾值

问：

我对 c++ 非常陌生，刚刚开始学习运算符重载。这是我的尝试

class Vector
{
 public:
 float x=0,y=0,z=0;
 Vector(float x, float y, float z) :x(x),y(y),z(z) {}
 Vector(Vector& copy) :x(copy.x),y(copy.y),z(copy.z){ std::cout << "Copy Created" << std::endl;} //Testing if any new objects were created during the operator overloading process[For my purpose this should not be called as no new objects should be created except than the returned result of each operator]

 public:
 Vector& operator+(Vector& v1) //return this+v1
 {
     Vector v(this->x+v1.x,this->y+v1.y,this->z+v1.z);
     return v;
 }
 Vector& operator-(Vector& v1) //return this-v1
 {
     Vector v(this->x - v1.x, this->y - v1.y, this->z - v1.z);
     return v;
 }
 Vector& operator*(Vector& v1) //return this cross v1
 {
     Vector v(this->y * v1.z-this->z * v1.y, -this->x * v1.z + this->z * v1.x, this->x * v1.y - this->y * v1.x);
     return v;
 }
}

std::ostream& operator<<(std::ostream& output, Vector& v)  
{
    output << v.x << "," << v.y << "," << v.z << std::endl;
    return output;
}

int main()
{
    Vector
    v1(1, 2, 3),
    v2(4, 5, 6);

    Vector
    v3 = v1 + v2,
    v4 = v1 - v2,
    v5 = v1 * v2;
  
    std::cout << v3 << v4 << v5;

  return 1;
}

打印时，所有 3 个向量都有垃圾值，并且每个操作调用了 copy 构造函数 3 次。我已经通过引用传递了每个向量，但仍然在我不理解的地方创建了一个新的临时实例。

我还尝试按照以前的线程的建议将关键字 const 添加到运算符及其参数中，但它并没有解决问题

由于我是新手，因此对解决方案的详细解释将不胜感激。谢谢