In a large bowl, whisk together the all-purpose flour, baking powder, baking soda, ground cinnamon, and fine sea salt; set aside.
In the bowl of a stand mixer fitted with the paddle attachment or in a very large bowl, beat the unsalted butter at medium speed with an electric mixer until smooth and creamy, then gradually add the granulated sugar and packed light-brown sugar and mix until light and fluffy.
Add the eggs one at a time, beating after each addition, then stir in the pure vanilla extract.
Gradually add the flour mixture and mix until just combined, then add the semisweet chocolate chips, old-fashioned rolled oats, flaked coconut, and chopped pecans and mix until fully incorporated into the dough.
Cover and refrigerate the dough for 12 to 24 hours.
When ready to bake, preheat the oven to 350°F and line baking sheets with parchment paper; remove the dough from the refrigerator and let it rest at room temperature while the oven preheats.
Use a large cookie scoop (¼ cup volume) to drop dough onto the prepared baking sheets, spacing the cookies 3 inches apart, and use the palm of your hand or the bottom of a glass to slightly flatten each ball of dough.
Bake for 16 to 18 minutes, until the edges are lightly browned; if desired, immediately top with flaky sea salt and allow the cookies to cool on the pans for about 5 minutes before transferring them to a wire rack to cool completely.