Umbrellas didn’t work for us either — they’d always catch the wind and topple over. What finally made our deck usable in summer was putting in a louvre roof (something like this: https://www.louvretec.com.au/products/838/louvretec-room). We can close it completely when it’s blazing hot, or just angle the slats to get some shade while still keeping the airflow. Honestly, it’s the only reason we actually spend time out there in summer now.
