One of the youtubers found an easy way to get into Red Dead Redemption 2 on the island of Guarma using a canoe. But this method has a small disadvantage, since you will have to row quite a lot and for a long time.
You will have to move South until the game itself will not let you know that you are on this island, the journey begins.
When you arrive at the river Bank, you will find a canoe, now you are sailing North. Now you have the longest route, you have to get out of the map and row further. When you see land on the right side, then row directly to it, the canoe will pass through it, and you will find yourself under the textures. Now you know how to get to the island Goarmy.