@Temo-Mori, I found this article that gives a couple different methods.

You could install blueutil and use that:

brew install blueutil

Then toggle it on or off like this:

blueutil on blueutil off

Or you could try this Apple Script method:

osascript -e 'tell application "System Events" to tell process "SystemUIServer" to tell (menu bar item 1 of menu bar 1 whose description is "bluetooth") to {click, click (menu item 2 of menu 1)}'