Moving a point next to cursor

Questions
1

I want a point to move next to the cursor. The problem is that I have OrbitControls implemented to system. I’ve tried to use:

      const vec = new Vector3();
      const pos = new Vector3();
      vec.set(
            (event.clientX / window.innerWidth) * 2 - 1,
            -(event.clientY / window.innerHeight) * 2 + 1,
            -1
          );
      vec.unproject(camera);
      vec.sub(camera.position).normalize();
      const vectorDistance = -camera.position.z / vec.z;
         
      pos.copy(camera.position).add(vec.multiplyScalar(vectorDistance));
      tempPoint.position.set(pos.x, pos.y, pos.z);

But there is a problem with z coordinate of mouse.