1. Grease inner pot with 1 Tbsp. softened butter. Toss peaches with flour, brown sugar, lemon juice, vanilla and, if desired, rum; spread evenly in inner pot. Whisk together first 6 topping ingredients; stir in oats. Cut in butter until crumbly; sprinkle over peaches. Cover with glass lid. Press slow cook function; select vegetables setting. Press timer; set to 4 hours. Start.
2. Remove glass lid; close air frying lid. Press air fry function; select custom setting. Press timer; set to 4 minutes. Start. Cook until the topping is lightly browned. Serve warm.