Bring a large pot of salted water to a boil. Add pasta and cook until just shy of al dente.
Reserve about 1 cup of pasta water, then drain.
Season the shrimp. Pat shrimp dry with paper towels. Toss with a pinch of salt, pepper, and half the red pepper flakes.
Start the sauce base. In a large skillet, warm olive oil over medium heat. Add half the butter and let it melt.
Add the garlic and cook 30–60 seconds until fragrant, not browned.
Cook the shrimp. Increase heat to medium-high. Add shrimp in a single layer and cook 1–2 minutes per side until just pink and opaque. Transfer shrimp to a plate to prevent overcooking.
Deglaze with wine. Pour in the white wine, scraping up any browned bits.
Simmer 2–3 minutes until slightly reduced and the alcohol smell softens.
Add lemon. Stir in lemon zest and juice. Add the remaining butter and swirl until glossy.
Build the sauce. Add a splash of reserved pasta water (start with 1/4 cup). Whisk or swirl to create an emulsified sauce that looks silky.
Toss the pasta. Add the drained pasta to the skillet.
Toss to coat, adding more pasta water as needed to loosen. Season with salt and pepper to taste.
Finish and serve. Return shrimp and any juices to the pan. Toss with parsley and the remaining red pepper flakes.
Sprinkle with Parmesan if using. Plate immediately with lemon wedges on the side.