Preheat your air fryer to 400 degrees Fahrenheit.
Slice the potato into thin wedges and toss in a bowl with one teaspoon of avocado oil, half the sea salt, and half the black pepper.
Place the potato wedges in the air fryer basket and cook for 15 to 18 minutes, shaking halfway through until they are tender and browned.
While the potatoes cook, pat the cod fillets completely dry with a paper towel and season with the remaining salt and pepper.
In a shallow bowl, whisk together the egg white, light beer, arrowroot powder, garlic powder, and onion powder until a smooth batter forms.
Place the panko breadcrumbs in a separate shallow dish.
Dip each piece of cod into the beer batter, let the excess drip off, then press into the panko breadcrumbs to coat all sides.
Remove the potatoes from the air fryer and keep warm; spray the basket with the remaining avocado oil and place the fish inside.
Air fry the fish at 400 degrees Fahrenheit for 10 to 12 minutes, flipping carefully halfway through, until the coating is crunchy and the fish flakes easily.
Steam the frozen peas in the microwave or on the stovetop for 3 minutes, then mash them with a fork and stir in the lemon juice.
Serve the crispy fish alongside the potato wedges and mashed peas for a clean take on a classic.