Place buckwheat groats and millet in a large bowl. Pour enough water to cover at least 2 inches from the top. Allow it to soak for 10 hours or overnight.
Pre-heat the oven to 350 degrees. Line a 9X5 loaf pan with parchment paper. Set aside.
Drain the buckwheat and millet combination in a strainer. Rinse well and set aside. (Buckwheat will be slimy so it is important to wash it well.)
Place psyllium whole husks in a bowl and add the 3 cups of water. Mix and set aside. 5-10 minutes should be enough.
Place rinsed buckwheat groats, millet, and 1 1/2 cups oats in the bowl of a food processor. Process until completely combined and grains are almost completely broken down, 45-50 seconds. You may have to scrape the bowl 1 or 2 times.
Add in the soaked pysllium husks, rest of the oats, baking powder, sea salt, and oil in the bowl of a food processor. Process until everything is combined, 30-45 seconds. Make sure to stop and scrape the bowl a couple of times.
Transfer the dough into the prepared loaf pan. Spread it out using the back of a spatula.
Combine flax, chia, sesame, and sunflower seeds in a bowl.
Sprinkle half of the seeds on top of the bread. Using a sharp knife, score the top of the loaf in several places. (For a visual, see the photo above)
Sprinkle the rest of the seeds and place it in the pre-heated oven.
Bake for 40 minutes. Remove and re-cut the places you scored earlier to let some of the air in for the inside of the bread to fully bake. Return it to the oven and bake for 55-60 minutes or until a knife inserted in the middle comes out slightly sticky.
Let it cool for 15 minutes on the kitchen counter and remove it from the pan.
Before slicing it, allow it to come to the room temperature.
You can store it in an airtight container for up to 4 days at room temperature or up to a week in the fridge.