@ symbol conflicts with IntelliJ shortcut
Apparently there is no solution for the moment (they are discussing about it since 2017) see here
With a lot of shame, I propose as a workaround to define a new live template in IntelliJ and use that one to type @. In my case, I type anno + tab and get the symbol without the git menu.
It is possible to disable the mnemonics for the menu and in this way Option + G does not open Git anymore. See here for reference.