Add 3 cloves garlic to skillet. Sauté garlic 60 seconds or until fragrant, then add half of ½ cup sliced green onions and sauté 30 to 60 seconds more.
Add 2 tablespoons fresh lemon juice, ¼ cup dry white wine, and ½ cup low-sodium chicken broth to skillet. Stir to incorporate, scraping up any bits of food that may have stuck to bottom of skillet.
Once incorporated, remove skillet from heat and let cool slightly. While mixture cools, add ½ cup heavy cream to heat-proof bowl.
Once slightly cooled, spoon 2 tablespoons of broth from skillet into heavy cream. Whisk broth into cream then repeat until all broth has been incorporated into cream. Pour tempered cream into skillet and stir to incorporate.
Return skillet to stovetop and bring mixture to boil. When liquids begin to boil, immediately reduce heat to low. Season with salt, freshly ground black pepper, and ⅛ teaspoon cayenne.
Stir to incorporate spices, then return bacon, shrimp, and mushrooms to skillet. Add remaining green onions and stir to incorporate. Simmer mixture until shrimp and bacon are just heated through.