W: GPG error: http://apt.radxa.com/focal-stable focal InRelease: The following signatures couldn’t be verified because the public key is not available: NO_PUBKEY 9B98116C9AA302C7
E: The repository ‘http://apt.radxa.com/focal-stable focal InRelease’ is not signed.
N: Updating from such a repository can’t be done securely, and is therefore disabled by default.
N: See apt-secure(8) manpage for repository creation and user configuration details.
Did the signatures expire again?