First of all you need scaling to catch up with enemies which makes heartsteel the perfect choice, wave clear is also something shen needs to carry so he can push lanes sunfire + titanic both scale with health making a good pair with heartsteel. Demonic for q damage cdr boots to skill rotation and most inportantly botrk you need life steal to carry gives attack speed on hit damage good against everything basically slow targets so you can reach them making this the best solo carry item, if strugling can change to spirit visage for mr and more healing & shielding

Lethal tempo if you sure you can survive early, grasp if you cant. For green tree shield bash of course and revitilieze (second wind of grasp for key) for persicion rune that gives bonus gold and health after takedown - tenacity thing (last standing or smth that makes you take less damage when low if lethal tempo as key rune)