Slice the sweet onion into thick rings and pat them dry with a paper towel to ensure the batter adheres properly.
In a medium bowl, whisk together the gluten-free flour, garlic powder, smoked paprika, sea salt, and black pepper.
Slowly pour the cold light beer into the flour mixture, whisking gently until a smooth, thick batter forms.
Dip each onion ring into the beer batter, allowing the excess to drip off before placing them in a single layer in the air fryer basket.
Toss the shrimp with avocado oil and a pinch of salt, then arrange them in the basket alongside the onion rings.
Air fry at 375°F for 10 to 12 minutes, flipping the onion rings halfway through, until the coating is golden and the shrimp are opaque.
Stir the non-fat Greek yogurt and lemon juice together in a small bowl to create a bright, creamy dipping sauce for serving.