Heat the oven to 425°F. Toss sweet potatoes with 1 tablespoon oil, 1/4 teaspoon salt and paprika on a large rimmed sheet. Roast for 25 to 30 minutes, turning once, until tender with browned edges.
Meanwhile, heat remaining oil in a skillet over medium-high heat. Cook beef and onion for 8 minutes, breaking beef into small crumbles, until it reaches 160°F. Drain excess fat.
Stir in garlic, ancho chile, cumin and 1/4 teaspoon salt for 30 seconds. Add broth and simmer for 3 minutes until the meat stays moist without loose liquid.
Toss cabbage with 1 tablespoon lime juice and remaining salt in a bowl. Stir remaining lime juice into yogurt in a separate small bowl.
Divide roasted sweet potatoes and warm beef among 4 bowls. Add cabbage slaw and avocado slices beside them, then spoon the lime yogurt over each serving.