Bring steaks to room temp. Pat the venison dry. Let it sit out for 20–30 minutes so it cooks evenly.
Season simply. Rub with 1–2 teaspoons olive oil.
Season both sides with kosher salt, black pepper, and a light dusting of garlic powder. Press in a few rosemary leaves or thyme leaves.
Preheat the air fryer. Set it to 400°F (200°C) for 5 minutes. A hot basket helps create a good sear.
Air fry the steaks. Place steaks in a single layer with space around them.
Cook 4–6 minutes, flip, then cook another 3–5 minutes. Aim for 125–130°F for medium-rare, or 130–135°F for medium. Use an instant-read thermometer for accuracy.
Rest the meat. Transfer to a plate and tent loosely with foil.
Rest 5–8 minutes so the juices settle.
Make the berry sauce. While the steaks rest, set a small skillet over medium heat. Add 1 tablespoon butter. Stir in berries, stock, 1 teaspoon balsamic, and 1 teaspoon maple syrup.
Simmer 3–5 minutes, breaking some berries with a spoon. You want a glossy, spoonable sauce, not jam.
Adjust and finish. Taste the sauce. Add a pinch of salt, more vinegar for brightness, or more maple for sweetness as needed.
Stir in orange zest if using. Grind in black pepper.
Slice and serve. Slice steaks against the grain. Spoon warm berry sauce over the top.
Garnish with extra herbs if you like.