2 pounds red plums, cut in 1/2, pitted, and cut in 1-inch wedges
2/3 cup granulated sugar, divided
1 1/4 cups all-purpose flour, divided
2 tablespoons orange juice
1/2 pint fresh raspberries
1/3 cup light brown sugar, packed
1/4 teaspoon kosher salt
8 tablespoons (1 stick) cold unsalted butter, diced
1/2 cup quick-cooking oats
1/2 cup sliced almonds, plus extra for sprinkling