Prepare the simple syrup by combining the powdered monkfruit sweetener and water in a small skillet. Stir to combine and heat until the sweetener dissolves completely, approximately 3-4 minutes. Remove from heat and set aside to cool.
Place the frozen pineapple, pineapple juice, coconut cream, rum, and one-quarter cup simple syrup into a blender and blend until smooth.
While the blender is still running, add the ice a little at a time until the desired consistency is reached.
Turn blender off and remove lid. Taste and add additional simple syrup, if desired, and blend for another 30 seconds to combine.