Honestly don't wait on all the web Dev to fix their app. Buy yourself a programmable keyboard that tells the computer they are a "normal US layout keyboard".
Now when you press "shift+7" on your keyboard it only sends "regular US keycode for /"
As a benefit you'll maybe also realize that Azerty or Qwertz are pretty bad layout for typing French/German, and you'll come up with something better.
If you do that you'll break anything that maps based on scancodes in order to have a consisten physical locations while the key label does not matter, like games with WASD for movement and nearby keys for shortcuts.
Now when you press "shift+7" on your keyboard it only sends "regular US keycode for /"
As a benefit you'll maybe also realize that Azerty or Qwertz are pretty bad layout for typing French/German, and you'll come up with something better.