I am using the MX Keys S. I would really like to see the ability to individually apply fn lock to certain f-keys. I want to be able to use common f-key binds like f5, f1, f2, and f4, while having quick access to the media controls of fn + f7-f12. It's one of the very few gripes I have with this keyboard. I always find myself inconvenienced regardless of whether fn lock is enabled or disabled, and I think this feature would let users have the best of both worlds.