Preheat the oven to 375°F and line a baking sheet with parchment paper. Brush the tortillas with melted butter, sprinkle with the sugar and cinnamon and cut into strips with a pizza cutter.Bake for 8 to 10 minutes until golden and crisp, let cool completely, then break into bite-size pieces.
Place a 9x5-inch loaf pan in the freezer. Add the cottage cheese, 1/2 cup dulce de leche, maple syrup, cinnamon, vanilla and salt to a high-speed blender and blend for 1 to 2 minutes until completely silky.
In a large chilled bowl, whip the heavy cream with a hand mixer until stiff peaks form, about 2 to 3 minutes.
Stir a large spoonful of the cinnamon mixture into the whipped cream to lighten it. Gently fold in the rest until smooth and evenly combined.
Microwave the remaining 1/4 cup dulce de leche for about 10 seconds so it becomes loose and drizzly.
Spread half of the ice cream into the chilled pan, scatter with one third of the crisps and drizzle with half of the dulce de leche. Repeat with the remaining ice cream, another third of the crisps and the rest of the dulce de leche, then swirl gently with a spoon.Save the last third of the crisps for serving. Press plastic wrap onto the surface and freeze for at least 6 hours or overnight.
Soften at room temperature for 10 minutes before scooping. Top each scoop with the reserved cinnamon sugar crisps for extra crunch.