Preheat oven to 350°F (175°C) and lightly grease an 8x8-inch baking dish.
In a large mixing bowl, combine the sliced peaches, 2 tablespoons maple syrup, lemon juice, vanilla extract, arrowroot powder, and 1/2 teaspoon of cinnamon.
Toss the peaches until evenly coated and transfer the mixture into the prepared baking dish.
In a separate bowl, stir together the gluten-free oats, almond flour, chopped pecans, remaining 1/2 teaspoon of cinnamon, and sea salt.
Add the melted coconut oil and 3 tablespoons of maple syrup to the dry ingredients, mixing until a crumbly texture forms.
Spread the oat topping evenly over the peach filling.
Bake for 35 to 40 minutes until the fruit is bubbling and the topping is golden brown.
Remove from the oven and let cool for 15 minutes to allow the juices to thicken before serving.