Whisk together the beef broth, soy sauce, and cornstarch in a small bowl to create the slurry; set aside.
Heat one tablespoon of avocado oil in a wok or large heavy skillet over high heat until it reaches the smoke point.
Add the steak strips in a single layer and sear for 2 minutes until browned; remove steak from pan and set aside.
Add the remaining tablespoon of oil to the pan and sear the shrimp for 2-3 minutes until opaque and pink; remove and set aside.
In the same pan, add the broccoli and bell peppers, stir-frying for 3 minutes until tender-crisp.
Add the garlic and ginger to the vegetables and cook for 30 seconds until highly fragrant.
Return the steak and shrimp to the pan along with any accumulated juices.
Pour the sauce mixture over the protein and vegetables, tossing constantly for 1-2 minutes until the sauce thickens and coats the ingredients.
Garnish with sliced green onions and serve immediately.