Preheat your air fryer to 400°F to ensure it is hot enough to crisp the potatoes.
Slice the russet potato into thin wedges, then toss them in a bowl with the olive oil and half of the sea salt and black pepper.
Place the potato wedges in the air fryer basket in a single layer and cook for 15-18 minutes, shaking the basket halfway through, until they are golden and crispy.
While the potatoes cook, prepare the batter by whisking together the whole wheat flour, light beer, garlic powder, and the remaining salt and pepper in a shallow bowl until smooth.
Pat the cod fillets completely dry with a paper towel so the batter adheres properly to the surface.
Dip each cod fillet into the beer batter, ensuring it is fully coated, and allow any excess to drip off.
Remove the potatoes from the air fryer and set aside, then lightly spray the basket with oil and place the fish inside.
Air fry the fish at 375°F for 10-12 minutes, carefully flipping the fillets halfway through, until the coating is browned and the fish is opaque.
Return the potatoes to the air fryer for 1-2 minutes to reheat, then serve the fish and chips immediately with a fresh lemon wedge.