If you are concerned about data loss from an external drive, you can buy another external drive of the same size and keep two backup copies of your data.
That way, if one of your external drives is damaged, you still have your data on the other external drive.
Example: Suppose you have a 1 TB external drive containing your data. Buy another 1 TB external drive, and keep another copy of your data in the second external drive. Each time you backup your data, you can back it up to both external drives.
To back up your data, you don't have to copy the entire data. Instead, you can use a program that only backs up files that have changed since the last backup. There are dozens of backup programs available. For example, you can use SyncBack on Windows.
You can also take an image of your external drive (for example, using Macrium Reflect on Windows), and save the image file somewhere. The disadvantage with this approach is that the data in an image file is not readily readable and accessible.