Preheat the oven to 350°F.
Line an 8 1/2 x 4 1/2-inch loaf pan with parchment paper, leaving some overhang for easy removal.
Whisk together the whole wheat flour, baking soda, cinnamon, and salt in a medium bowl.
Mash the very ripe bananas until mostly smooth.
Add the eggs, maple syrup, Greek yogurt, olive oil, and vanilla to the mashed bananas.
Whisk the wet ingredients until well combined.
Add the dry ingredients to the wet mixture.
Fold gently with a spatula just until no dry streaks remain. Do not overmix.
Transfer the batter to the prepared loaf pan.
Smooth the top evenly.
Bake at 350°F for 50–60 minutes.
Check the center with a toothpick; it should come out with a few moist crumbs but no wet batter.
Let the banana bread cool in the pan for 10 minutes.
Use the parchment overhang to lift the loaf onto a wire rack.
Let it cool further before slicing.