You can restore the missing Bluetooth icon in Taskbar notification area of Windows 11/10 if it is not showing via Settings or Control Panel.

If the Bluetooth icon is missing on the Quick Settings panel on your Windows 11 computer, then you can add it by editing these settings.

The same is happening for the Bluetooth icon in Android P. On P, you can leave your Bluetooth turned on without it causing an icon to show permanently in the status bar.