Preheat your air fryer to 400°F (200°C).
Slice the Russet potato into thin wedges, toss them with half of the olive oil and a pinch of sea salt.
Place the potato wedges in the air fryer basket and cook for 15-20 minutes, shaking halfway through, until they are golden and crispy.
While the potatoes cook, pat the cod fillets completely dry with a paper towel and cut them into large strips.
In a small mixing bowl, whisk together the arrowroot starch, almond flour, garlic powder, paprika, remaining salt, and black pepper.
Slowly whisk the light beer into the dry ingredients until a smooth, thick batter forms.
Dip each piece of cod into the batter, ensuring it is fully and evenly coated.
Lightly grease the air fryer basket with the remaining olive oil, place the battered fish inside without crowding, and air fry at 375°F for 10-12 minutes until the coating is crisp and the fish flakes easily.
Serve the hot fish alongside the potato wedges immediately.