One of my favorite passages from the Meditations is Marcus' observation that Stoicism has value regardless of one's theology and metaphysics:
Either there is a fatal necessity and invincible order, or a kind Providence, or a confusion without a purpose and without a director. If then there is an invincible necessity, why do you resist? But if there is a Providence that allows itself to be propitiated, make yourself worthy of the help of the divinity. But if there is a confusion without a governor, be content that in such a tempest you have yourself a certain ruling intelligence. (XII.14)
Either there is a fatal necessity and invincible order, or a kind Providence, or a confusion without a purpose and without a director. If then there is an invincible necessity, why do you resist? But if there is a Providence that allows itself to be propitiated, make yourself worthy of the help of the divinity. But if there is a confusion without a governor, be content that in such a tempest you have yourself a certain ruling intelligence. (XII.14)
https://howtobeastoic.wordpress.com/2016/01/02/gods-or-atoms...
I have found Stoicism an ecumenical movement in part because of the above.