Grate zucchini using a box grater and squeeze out excess moisture with paper towels. Set aside.
Preheat to 350°F (175°C). Line an 8x4-inch loaf pan with parchment paper for easy removal. Lightly grease the sides.
In a large bowl, mash overripe bananas until mostly smooth. Whisk in maple syrup, melted coconut oil, vanilla extract, and non-dairy milk until combined.
In a separate bowl, whisk together purpose flour, oat flour, almond flour, vegan protein powder, coconut sugar, baking soda, salt, and cinnamon.
Add dry ingredients to wet ingredients, folding gently until almost combined. Do not overmix.
Fold in grated zucchini and most of the chocolate chips (reserve some for topping).
Bake
Pour batter into the prepared pan. Sprinkle remaining chocolate chips on top. Bake for 50–55 minutes, checking at the minute mark to ensure a toothpick comes out clean.
Let the entire loaf rest in the pan for 10 minutes, then transfer to a wire rack to let the bread cool completely before slicing into thick slices.