Preheat the oven to 350°F (175°C) and grease a 13 x 9 baking dish.

In a mixing bowl, combine strawberry cake mix, guava juice, eggs, and melted coconut oil. Mix on medium speed for about 2 minutes until smooth.

Pour the batter into the prepared baking dish and bake for 24-26 minutes, checking for doneness with a toothpick.

Let the cake cool in the pan for 10 minutes, then transfer to a wire rack to cool completely.

Beat cream cheese in a mixing bowl until fluffy, then mix in sugar and vanilla. Fold in Cool Whip until smooth.

In a saucepan, combine guava juice and sugar, and bring to a boil. Whisk cornstarch and water into a slurry, then stir into the boiling mixture until it thickens.

Spread the cream cheese mixture over the cooled cake, then pour the guava gel on top.

Refrigerate the assembled cake for at least 2 hours before serving. Optionally, sprinkle with coconut flakes before serving.