Preheat your air fryer to 400°F to ensure a high-heat environment for maximum crunch.
Slice the potato into thin wedges, toss with half the avocado oil and a pinch of sea salt, and air fry for 15 minutes.
In a shallow bowl, whisk together the almond flour, arrowroot powder, garlic powder, salt, pepper, and beer until the batter is smooth and aerated.
Pat the cod fillets completely dry with a paper towel to help the batter adhere, then lightly coat with the remaining oil.
Dredge the fish into the batter until fully submerged and coated, then place into the air fryer basket.
Air fry the fish at 375°F for 10-12 minutes, flipping halfway through, until the coating is golden-brown and shatteringly crisp.
Serve the hot fish and chips immediately with a fresh lemon wedge for a bright finish.