Issue: Diagonally movement

Hello there I'm having an error with my player's movement, it strangely goes diagonally if moved as well as going in the direction performed. (I use the input system with a Vector2 value in normalized process)

Plus I was wondering if Constraints should be used to lock rotations, why and how should I use them What is the optimal way to ensure that the player remains in his employ?

RIGIDBODY COMPONENT: https://ibb.co/kSzs50r

 private void Move()
     {
         if (!_hasAnimator) return;
 
         float targetSpeed = _inputManager.Run ? _runSpeed : _walkSpeed;
         //if (_inputManager.Crouch) targetSpeed = 1.5f;
         if (_inputManager.Move == Vector2.zero) targetSpeed = 0;
 
         if (_grounded)
         {
             _currentVelocity.x = Mathf.Lerp(_currentVelocity.x, _inputManager.Move.x * targetSpeed * _indexSpeed, AnimBlendSpeed * Time.fixedDeltaTime);
             _currentVelocity.y = Mathf.Lerp(_currentVelocity.y, _inputManager.Move.y * targetSpeed * _indexSpeed, AnimBlendSpeed * Time.fixedDeltaTime);
 
             var xVelDifference = _currentVelocity.x - _playerRigidbody.velocity.x;
             var zVelDifference = _currentVelocity.y - _playerRigidbody.velocity.z;
 
             _playerRigidbody.AddForce(transform.TransformVector(new Vector3(xVelDifference, 0, zVelDifference)), ForceMode.VelocityChange);
         }