In order to get the easiest win of your life, you wil have to do some pre-game preparations.
Firstly you'll have to pick a duel map:
secondly, in advanced settings set you opponent to be Mvenba a Mzinga of Kongo.
We'll be going for a very fast religion win, and the less players there are in the game, the easier the religious victory. Additionaly we pick Mvemba as our opponent, because he'll never attack you as long as you spred your religion to him + he cannot create a religion to counter yours.
I suggest picking aztec empire as your civilization. They are able to sacrifice builder charges in order to build Holy site faster. Also in order to make sure that the ocean won't stop you pick Terra map.
Pre game settings:

As soon as the game starts you want to rush astrology. At the beggining you should rush a builder. He will help you, to build your Holy site very fast. After researching astrology you should go for mining, in order to be able to chop some forests and build mines on the hills, to get some extra production. After that your science really doesn't matter that much, so you can f.e. go for Hagia Sophia I guess?Try to maximize the production and don't worry about snowballing the game. Try to build holy site as soon as you can in order to acquire the great prophet points . You should plug in god king, to rush pantheon. In Civics tree you should rush theology. For your pantheon, if you have a starting location, that will give a lot of faith with one of the pantheons, pick it. Otherwise, pick Divine spark for +1 great prophet point on your Holy site.
Turn 22, I have builders ready to sacrifce charges to Holy site.

Holy site completed in 3 turns thanks to builders we made earlier.:

Then you should go for shrine.
This time, you can chop woods in order to complete it faster.

After that, finally go for the scout to find Mvemba. Make sure to send him a delegation. As for your city do Holy sites Prayers for the rest of the game, stopping only if you can build a temple. When you can, buy a trader to make extra religious pressure on Kongo.
As for the beliefs, if you managed to find a relic pick Reliquaries and Holy order. Otherwise pick Work ethic instead.
Prophet & religion on turn 42:

Beliefs pannel(Relic not found):

After that spam missionaries and get the win!
He's friendly, cause we satisfy his agenda:

And win on turn 68:

Thanks for reading! If the guide helped you, be sure to like or even award me UwU.