Get mouse x,y,z coordinates depending on camera rotation

Hi I’m trying to get the delta movement of my mouse in a 3d scene in every axis depending on cameras rotation without using Raycasting. Could anyone point me in a correct direction.
Im able to get a 2d delta translation but im not sure on how to apply cameras rotation to know which axis apply it to. (x,y | z,x etc).

_getMousePositionInScene(mousePos) {
        let vector = new Vector3(mousePos.x, mousePos.y, 0);
        vector.unproject(this.camera);
        let dir = vector.sub(this.camera.position).normalize();
        let distance = - this.camera.position.z / dir.z;
        let pos = this.camera.position.clone().add(dir.multiplyScalar(distance));
        return pos;
    }

Thanks in advance