So I'm wanting to add a Bluetooth button on BTT that when I press it, it pulls up the list of Bluetooth devices you can connect to. I've read that there are scripts for connecting to a specific device, but I switch between quite a few. So being able to pull up the setting and then clicking on one would be really convenient.
You are just wanting to open the bluetooth menu from the menubar? Like this one?
If yes, then add a new widget, and select the predefined action as 'Run Apple Script' (async). The following script should work:
tell application "System Events" to tell process "SystemUIServer"
set btMenu to ( first menu bar item whose description is "bluetooth") of menu bar 1
click btMenu
end tell
Although one note is that for this to work, you must have the bluetooth icon in your menubar.