That doesn't turn Bluetooth off. It's deceptive. It simply "disconnects" it, but it'll still connect at a random point in the future. It also doesn't really disconnect it since it'll still detect devices and burn away your battery life. And I experimented with it countless times over a couple years.

That's why I said you need to do it through settings directly. Otherwise it won't do anything.

Yes it does. Once you tap that button Bluetooth will remain off.

Yes, but only until the next day.

It absolutely does not. I've tried it countless times and my AirPods still drain overnight if I use the drop down disable. I've also disabled it that way and seen an "AirPods detected" message minutes later.

Apple themselves even says if you want to turn off Bluetooth, you need to do it through settings: https://support.apple.com/en-us/102412

This is accurate.

It is not. Apple themselves say you need to go to settings to turn it off: https://support.apple.com/en-us/102412

Otherwise it's merely a temporary disconnect.