Preheat your air fryer to 400°F.
Slice the russet potato into thin, even wedges.
In a bowl, toss the potato wedges with 0.5 tbsp of olive oil, half of the sea salt, and half of the black pepper.
Place the potatoes in the air fryer basket in a single layer and cook for 15-20 minutes, shaking halfway through, until golden and crisp.
While the potatoes cook, pat the cod fillet dry with paper towels and season with garlic powder, paprika, and the remaining salt and pepper.
In a small shallow bowl, whisk together the flour, light beer, and egg white until a smooth batter forms.
Lightly brush the remaining 0.5 tbsp of olive oil onto the air fryer rack or a piece of perforated parchment paper.
Dip the seasoned fish into the beer batter, ensuring it is fully coated, and let any excess drip off.
Lower the air fryer temperature to 375°F and place the fish inside. Cook for 10-12 minutes, flipping gently halfway through, until the batter is golden brown and the fish flakes easily with a fork.
Serve the crispy fish immediately alongside the hot potato wedges.