You get lounge access as a OW Sapphire. There is a sleeping room in the Sumaq (assuming the lounge is not at capacity when you arrive and you are sent to the VIP) but with only 5 (is that correct?) chaise lounges I imagine the competition for them would be stiff during the overnight hours. I would make a beeline directly for one of them if I were you. The room is on the right after the entrance, between the business center and the restrooms.