Heat oil in a large Dutch oven or other heavy pot over medium.
Cook shallot, garlic, and ginger, stirring often, until shallot is softened and translucent, about 3 minutes.
Add miso and cook, stirring, 1 minute.
Add squash, salt, maple syrup (if using), and 4 cups water and stir to combine.
Bring to a boil, then reduce heat and cover pot.
Cook until squash is very tender, 20–25 minutes.
Carefully purée squash and cooking liquid with an immersion blender until smooth.
Bring squash purée to a simmer over medium heat.
Stir in lemon juice; taste and season with more salt if needed.
Divide soup among bowls and top with cilantro, chili crisp, and peanuts.
Serve with lemon wedges for squeezing over.
