PreparationFor the dashi: Bring mushrooms, ginger, chile, garlic, kombu, turmeric, and 4 1/2 cups water to a simmer in a medium saucepan over medium-high heat. Cover, reduce heat to very low, and gently simmer 25 minutes to allow aromatics to infuse and flavor the water. Strain dashi through a fine-mesh sieve into a large bowl; discard solids. Wipe out saucepan and pour dashi back in. Return to a simmer. Mix miso and 1 Tbsp. dashi in a small bowl, then stir into dashi in pan along with soy sauce; season with salt. Keep dashi hot if using right away. Do Ahead: Dashi can be made 2 days ahead. Let cool, then transfer to an airtight container and chill. For the noodles and assembly: Heat olive oil in a medium skillet over medium-high. Cook mushrooms, stirring occasionally, until golden brown and beginning to crisp, about 5 minutes. Remove from heat, finely grate garlic over mushrooms, and mix well (garlic will cook in residual heat of mushrooms). Season with salt. Drop noodles into very hot dashi. Cover pan and let sit 3 minutes. Divide noodles and dashi among bowls. Top with mushrooms, radishes, herbs, fermented vegetables, and sesame seeds; drizzle with hot sauce and sesame oil.