To that excellent guide, I would in addition recommend this awesome tutorial on the usage of “snapper”, which is a CLI tool which automates the creation and management of snapshots. It’s sort of like Timeshift, but not GUI (so snapper is great for headless servers, while Timeshift is moreso for the desktop).
If you ever make your own headless NAS, with BTRFS on your served-out disks, you’ll probably want to use snapper.