I still got the same error message.It looks like an error related to the Ubuntu software repository keys.
You can try running the following commands to update the repository keys:
sudo apt-key adv --keyserver keyserver.ubuntu.com --recv-keys 6B073B6950B31B580B1D75015DCF8AE37F729B06 sudo apt update
These commands should download and add the missing keys to the repository keyring, and then update the package information from the repositories.
After running these commands, you can try running the Discord command with sudo again to see if it resolves the PTT keybinding issue.
Let me know if this helps or if you have any other issues or questions!