I've used CCC for almost as long as it has been around, and it is an outstanding program. Inexpensive, updated regularly (usually at no cost), and very well supported with extensive documentation. CCC has a bit of a learning curve, but that is inevitable given the number of ways it can be configured to individual needs. I back up photo and work files to no fewer than four external hard drives. While my computer's working drive is a four-disk RAID 5, I do not use a RAID system for backup. RAIDs can completely fail, which I have unfortunately experienced. A hardware problem once wiped out a year's worth of files on a RAID external I was using. It took out all the disks comprising my RAID. RAIDs are great systems, and provide security in almost all cases, but they are not 100% infallible.
So, I back up important files directly to individual external drives, known as JBOD (just a bunch of disks). No RAID. Yes, it means that I must run CCC for each disk, a bit tedious, but I really don't care since CCC runs in the background.
I have a SSD internal in my iMac as a startup drive, containing only system files and applications. All my work files are on the aforementioned external four-disk, 12 TB RAID. CCC allows me to configure two individual backup "drives" on a single external disk in a partition-like allocation. So, I back up my startup SSD to one "drive," cleverly named "Backup SSD," and I back up all work and photo files to another "drive" on the same external, having the name "Master." This allows me to keep startup and work files separately on a single large external HD, avoiding a proliferation of disks. CCC also allows me to configure different backup protocols for each. Make sure, however, you completely understand how CCC works before attempting this kind of setup. When the external disks get full, I pull them out of the enclosure, label them by year, store them away, and simply install new drives which are relatively inexpensive. OWC offers several drive enclosures allowing you to do this.
Should I need to access a file from years ago, I have an inexpensive little device that reads a "naked" disk. No need to reinstall the drive in the original enclosure.
This system gives me as close to 100% security as is possible, short of Armageddon. In the case of Armageddon, I will have bigger concerns than my backups.
I also run Time Machine to a single external 8TB drive. TM is a great program, and many people don't realize that it has different configuration options, too. But, it is important to remember that TM is not an "archival" backup. It is primarily designed as a point-in-time backup that allows you to completely restore a Mac to its most current configuration in the event of a total hardware failure. It is also handy for recovering files from an earlier date if you've inadvertently deleted a file or need to look at a previous version. TM will, however, automatically delete and overwrite the oldest files when the drive becomes full. This is why it is not considered "archival."
CCC allows you to configure in a number of different ways how older files are handled, well beyond what TM allows. CCC and TM used in tandem, are an ideal combination.
Hope this helps.