Combine seed mix for topping and soak ½ cup water with the seed mixture for the dough; let sit 30 minutes to overnight.
Mix flours, yeast, honey, melted butter, remaining water, oats, and salt in a stand mixer; knead 6-8 minutes until elastic dough forms.
Add the soaked seeds and water to the dough; mix until fully incorporated. Let rise covered 1-1.15 hours until doubled.
Preshape, shape into loaves, and let rest 10 minutes. Final shape into logs, coat with beaten egg white, then roll in seed topping. Place in loaf pans and let rise 45-60 minutes.
Bake at 375°F (190°C) for 35-40 minutes until golden and internal temperature reaches 185°F (85°C). Cool before slicing.
Notes
Ensure the dough is elastic enough to pull a windowpane for proper gluten development.