Preheat your air fryer to 400°F. Slice the russet potato into thin wedges.
Toss the potato wedges with half of the avocado oil and a pinch of sea salt. Air fry for 15-18 minutes until golden and crisp, shaking halfway through.
In a shallow bowl, whisk together the arrowroot powder, garlic powder, black pepper, and the remaining sea salt.
Slowly pour the cold non-alcoholic beer into the arrowroot mixture, whisking until a smooth, thin batter forms.
Pat the cod fillets completely dry with paper towels. Dip each fillet into the batter, ensuring it is fully coated.
Lightly grease the air fryer basket with the remaining avocado oil. Place the battered fish in the basket, ensuring they do not touch.
Air fry the fish at 375°F for 10-12 minutes, flipping gently halfway through, until the coating is shattering-crisp and the fish is opaque.
While the fish cooks, steam the green peas until tender. Mash them roughly with a fork and stir in the finely chopped fresh mint.
Serve the crispy fish immediately with the golden fries and a side of the minty crushed peas.