Linux

I am using Borg for years. So far, the tool has not let me down. I store the backups on external hard drives that are only used for backups. In addition, I save really important data at rsync.net and at Hetzer in a storage box. Which is not a problem because Borg automatically encrypts locally and for decryption in my case you need a password and a key file.

Generally speaking, you should always test whether you can restore data from a backup. No matter which tool you use. Only then you have a real backup. And an up-to-date backup should always additionally be stored off-site (cloud, at a friend's or relative's house, etc.). Because if the house burns down, the external hard drive with the backups next to the computer is not much use.

By the way, I would advise against using just rsync because, as the name suggests, rsync only synchronizes, so you don't have multiple versions of a file. Which can be useful if you only notice later that a file has become defective at some point.