Time Machine vs Carbon Copy Cloner

You're way overthinking things.

I never had a backup strategy. I usually have my most important files and photos uploaded manually in the iCloud and I also have an external SSD where I store my most important files.

That is the definition of a backup strategy.

Everyone's work needs and commensurate backup requirements are different. You have to decide which works best for you, but if you have lost personal photos a few times it suggests you need to review that strategy.

I have also purchased CCC but I admit I don't know how to use it.

I believe they have robust support and documentation.

Also it is my "OCD", I am trying to use as much as possible the macOS built-in tools and try not to over-bloat my system so I am installing only the minimum tools needed.

Then use TM. It's already installed. There are no additional tools to install.

So, I want to understand, is CCC bringing any benefits over the Time Machine? I don't want to have automatic backups, all I want is one time a week or once several days to backup my system on an external disk, manually. This backup I think is enough for me. I don't want to have snapshots to return in time. What is the difference between CCC and Time Machine? Is it any better? I already purchased CCC 7 (the price is not so high). What is the best strategy for backup? What is this 3 2 1 strategy?

People grow fond of their idioms and their trite little rules of thumb, but when important details become lost in them then they are performing a disservice. If you ask a "3 2 1 strategy" means, you will get different answers, leading to confusion. So what benefit does that cutesy expression convey? You decide.

The bottom line is use what works. For me, a robust backup strategy means that all backups are never in the same geographical location. Simple math means at least three separate backup devices will be required, so that one of those backups are never in the same place at the same time as the other two. Since a backup disk needs to be connected to the source Mac when it backs up, a single catastrophic event — ranging from a lightning strike to a flood to simple user error — can simultaneously destroy two. One copy of your data remains — the one stored separately. Is that enough? You decide. Use what works for you.

Use Time Machine on your Mac to back up to multiple disks - Apple Support

I need advice from people doing this.

I have been using TM since its inception and have had zero failures to back up or restore. Before then I used a different commercial product that worked somewhat like it, but TM made it obsolete. I had also used CCC for some time in the past but determined that it did not offer any advantages. There is nothing wrong with that product though. Use it if you want. It's fine. But like any backup strategy you have to use it.

My internal MacBook has a 4 TB drive and I have two external SSDs of 4 TB each.

That won't work. Because...

Time Machine requires double the internal storage

TM ideally requires at least 2x the storage capacity of the source disk. You might be able to get away with less depending on the amount of internal storage that is actually used, but determining the latter has become difficult due to the way macOS manages that internal storage. It's not obvious, and it varies widely. Use 4 GB or larger external hard disk drives and it won't be a concern.

I don't want to have automatic backups, all I want is one time a week or once several days to backup my system on an external disk, manually.

Then don't connect your backup disks but one time a week or once several days. Time Machine will work anyway. Backups will be written to disk whenever they are connected. If you forget to connect them, TM will complain after ten days have elapsed. Backing up to a NAS means you won't have to remember to connect anything, but that's beyond the scope of your question. For that I use Time Capsule but Apple is being quite vocal about the fact they will no longer be supported in the near future. Since I have used a non-Apple NAS device in the past and concluded it was not reliable, I am developing another solution of my own design in anticipation of Time Capsule going away.

Some people use both CCC and TM. CCC is a fine product that I used in the past but determined that it did not offer any significant advantages over TM.

Part 2 of this longwinded reply follows below.

If you have used or are using Time Machine Backup Utility  you maybe able to Restore the Deleted Files 

IMHO, it is better to use the default schedule

Running it manually every very so often would leave Time Gaps between the last backup and the current backup

Time Machine automatically makes hourly backups for the past 24 hours, daily backups for the past month, and weekly backups for all previous months. The oldest backups are deleted when your backup disk is full.

To truly protect your non replaceable Data

Have a 3-2-1 Rescue Plan in place and always current

3 Backups using 2 methods and 1 off site incase of natural disaster or un-natural disaster.

Each of the above should be done to a Dedicated Single Purposed External Drive. That last point is very important

Using a Single Drive for more than one purpose spells trouble

Below link is intended to augment what TM Backup does 

https://bombich.com

Much like TM Backup, Carbon Copy Cloner does offer the abilities to Schedule Backups

https://support.bombich.com/hc/en-us/articles/20686449773847-How-to-schedule-a-backup

That would be a user choice to do this or not to

Personally, use TM Backup on default schedule and use Carbon Copy Cloner and a Manual Basis. Usually the last thing I do before my days end and just before shutting down

I don't want to have automatic backups, all I want is one time a week or once several days to backup my system on an external disk, manually.

You can do that with either of them.

This backup I think is enough for me. I don't want to have snapshots to return in time.

I think you are confusing the marketing with the function. Every backup system allows you to choose the point in time from which you restore. Apple made it more interactive than just picking a date from a list of incremental backups. If you are just erasing the previous backup and not doing incremental backups, I think CCC might be easier to set up that way, but not certain.

What is the difference between CCC and Time Machine? Is it any better? I already purchased CCC 7 (the price is not so high).

I use CCC to backup external data drives, but I use Time Machine for the startup drives. I don’t really know how CCC works. Time Machine leverages a system database that logs every change in the file system real-time. It doesn’t have to scan every file to see if it is different from the backup (that is the traditional way backups worked before Time Machine).

Time Machine is designed to just enable it and forget all about it. CCC allows more customization of what and how. That requires you to make decisions about the future when you set it up. It’s not difficult, but more difficult than Time Machine.

Reply Part 2 of 2

A successful backup strategy is the one that gets used. Time Machine's advantages is that you turn it on and forget about it. Maybe CCC does the same thing; I don't know, but TM is highly integrated in macOS, it works, and it's reliable.

I don't want to have snapshots to return in time.

But that's what Time Machine does... hence the name.

Also I am not interested in snapshots, just simple backups.

System snapshots are used by Time Machine. Read About Time Machine local snapshots - Apple Support to learn what they are, and Connect a new backup disk to your Mac - Apple Support to learn how they are used.

As I wrote you are overthinking things and your OCD is leading the way toward complication.

After connecting and formatting your backup disks Time Machine works like this:

1. Turn it on
2. Forget about it

That's it. Your OCD won't like it though. It's too simple. Your OCD is telling you something as important as backups can't be that simple... but it is. There is nothing else like Time Machine in that regard.

If CCC works the same way, then go ahead and use it. You can certainly use both, but that strikes me as complicated where a backup strategy should be simple. As I wrote several times though, up to you to determine what works best.

@Barney-15E

If I may share visa vie CCC Safety Net Snapshots vs Backup snapshots , if this is any use

https://support.bombich.com/hc/en-us/articles/21384579432343-SafetyNet-snapshots-vs-Backup-snapshots