Preheat your air fryer to 400°F (200°C).
Slice the russet potato into thin, even wedges and pat them dry with a paper towel.
In a bowl, toss the potato wedges with 0.5 tbsp of avocado oil and a pinch of sea salt.
Place the potatoes in the air fryer basket in a single layer and cook for 15-18 minutes, shaking halfway through, until golden and crisp.
While the chips cook, whisk together the flour, light beer, garlic powder, paprika, sea salt, and black pepper in a shallow dish until a smooth batter forms.
Pat the cod fillets completely dry, brush with the remaining 0.5 tbsp of avocado oil, and then dredge each piece through the beer batter until fully coated.
Carefully place the battered fish into the air fryer basket next to the potatoes and cook at 400°F for an additional 10-12 minutes until the coating is set and the fish is opaque.
Serve the fish and chips hot, optionally garnished with a wedge of fresh lemon.