Preheat your air fryer to 400°F.
Slice the russet potato into thin wedges, pat them dry with a paper towel, and toss with 0.5 tbsp of avocado 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 golden and crisp.
While the fries cook, pat the cod fillet dry and season both sides with garlic powder, paprika, sea salt, and black pepper.
In a small shallow bowl, whisk together the all-purpose flour and light beer until a smooth, thick batter forms.
Heat the remaining 0.5 tbsp of avocado oil in a non-stick skillet over medium-high heat.
Dip the seasoned fish into the beer batter, allowing any excess to drip off, then carefully place it in the hot skillet.
Sear the fish for 3-4 minutes per side until the batter is golden brown and the fish flakes easily with a fork.
Serve the crispy fish immediately alongside the hot potato wedges.