Backup of GPG private keys?

[Mogens Jensen]

As of GnuPG (LTS) version 2.2.33, what is the recommended way to backup
your GPG private keys on a Linux system?

1. Backing up the entire ~./gnupg directory?
2. Exporting only the keys?

  $ gpg --armor --export-secret-keys >gpg-key-backup.asc

Thanks.