Add a copy for the existing repository
A 3-2-1 strategy means having at least 3 total copies of your data, 2 of which are local but on different mediums (read: devices), and at least 1 copy offsite.
I'm not using 2 local backups right now. For me, Using a second local backup is only useful when the speed and the cost of restoring data matter. Currently, I use Google Drive as the second backup to reduce the cost of restoring backup from Backblaze B2.
Google Drive can be mounted as local directory using rclone. I did think about using it as a cloud storage for self-hosted services, including Jellyfin or NextCloud. But running rclone needs a server to run all day in order to be accessible on mobile devices. For such purpose, either buying a server that has big storage to avoid the need of Google Drive or buying a server that has excellent network for user experience with Google Drive mounted can be considered. For now, I go with the first plan.