The manduka opanisha teaches exactly what all the openithas teach. It tells us that you are one with god, you are the ultimate reality. This world and how we experience ourselves are manifestations of that reality. If only we would know ourselves truly, we would realize ourselves to be that absolute reality. That Absolute Reality is called brahman in vedanta - which means vast.
Swami Sarvapriyananda speaks on “The Essence of All Vedanta” at the Vedanta Society of New York - April 8, 2018 | Vedanta NY