It’s time to end this madness. In all these apps, both audio and video are _enabled_.
Skype, Meet and Zoom use non-crossed icons to indicate that.
Face Time and Whatsapp use crossed icons.
Telegram uses crossed mic icon but non-crossed camera to indicate that both are enabled.
This mess means only one thing: both ways are wrong. You can’t indicate mute/camera state with a single icon. Whatever your reasoning might be, it’ll always be confusing. Don’t try.
Instead, use a control that clearly displays both states at once. I drew one for you. Feel free to copy. I’ll be only happy.