Adjust rack to upper position and preheat oven to 450 degrees. Wash and dry all produce. In a large microwave-safe bowl, combine 5 cups water and stock concentrates; microwave until hot, about 5 minutes. Thinly slice garlic. Halve, peel, and mince shallot. Zest 1 tsp zest from lemon; quarter lemon.

Heat a drizzle of oil in a large pan over medium heat. Add shallot and garlic. Cook until softened, 1-2 minutes. Add rice and stir until translucent, 1-2 minutes. Add stock mixture to pan, 1/2 cup at a time, stirring after each addition. Allow rice to absorb most of the stock before adding more. Continue until rice is al dente and creamy, 30-35 minutes.

Meanwhile, pick sage leaves from stems; thinly slice leaves. Toss squash on a baking sheet with a drizzle of oil and a pinch of salt and pepper. Roast until browned and tender, 15-20 minutes.

Meanwhile, pat scallops dry with paper towels and season generously all over with salt and pepper. Heat a large drizzle of oil in a separate large pan over medium-high heat. Add scallops and cook until browned and just firm, 3-5 minutes per side. Remove from pan and set aside, covered, to keep warm. Wipe out pan.

Melt 2 TBSP butter in same pan used to cook scallops over medium heat. Cook, stirring often, until butter is foamy on top and flecked with amber brown bits, about 3 minutes. Stir in 1 tsp sage and a squeeze of lemon juice. Carefully transfer to a small bowl. Once risotto is al dente, stir in squash, lemon zest, Parmesan, 1 TBSP butter, and a squeeze of lemon juice.

Taste and season risotto with salt, pepper, and more lemon juice if needed. Divide between bowls. Top with scallops. Drizzle with brown butter. Garnish with remaining sage (to taste). Serve with any remaining lemon wedges on the side.