This annoyed me too, but I worked out a solution to having to go into Settings or airplane mode every time you want to disable wifi: Make a Shortcut for it and

This annoyed me too, but I worked out a solution to having to go into Settings or airplane mode every time you want to disable wifi: Make a Shortcut for it and make that shortcut an icon on the home screen. I made a Shortcut icon named All Off that fully turns off WiFi, Data, and Bluetooth with one press. Easy to set up in the Shortcuts app.