Unless you are something a of an archaeology/history geek, ditch Saqqara.
Engage guides. They are not expensive, keep a lot of hassle away and tell you stuff. Just don't be afraid to tell your guide what you want to see and what you want to hear - otherwise there's a tendency to open the taps on three years' training in Egyptian history and iconography.
Arriving at 6pm, hotel by 6:30pm at Karnak by 7:30 seems a tad ambitious!
I don't know how Uber and Careem operate in Luxor, but I'd be prepared for a bit of light chaos at the airport. You'll probably need a SIM card - don't depend on the airport's Wifi!