Bring a large pot of lightly salted water to a boil. Cook angel hair pasta in the boiling water, stirring occasionally, for about 1 minute less than recommended, 3 to 4 minutes. Reserve 1/4 cup pasta water. Drain pasta and return to the pot.

Heat 1 1/2 tablespoons butter and 1 1/2 tablespoons olive oil in a 12-inch skillet over medium-low heat. Add garlic and 1/4 teaspoon salt, cook until fragrant, about 1 minute, being sure not to burn. Add zucchini, yellow squash, shishito peppers, and pepper flakes; saute until vegetables begin to soften, 3 to 5 minutes.

Spread vegetables to the outside of the skillet. Add remaining butter and olive oil to the center of the skillet and increase heat to medium. When butter has melted, add shrimp to the center of the skillet, and peas to the outside. Toss shrimp to cook for 2 to 3 minutes, then toss to mix with vegetables. Add reserved 1/4 cup pasta water and bring to a gentle boil, about 3 minutes. Remove from the heat.