Is it possible to use time machine to synch photos in external hard drive like Lacie? I edit in Lightroom/

iCloud is a syncing solution, meaning you can have documents save in iCloud that are automatically accessible to your Mac, iPhone, iPad etc...

Backup, is making copies of data in the event your device (Mac, iPad, iPhone etc..) crashes and loses the data stored on it.

The terms "syncing" and "backup" have completely different definitions.

A Time Machine backup will backup all drives that are attached to the Mac. You should carefully read : https://support.apple.com/en-us/HT201250

Time Machine is a app for backup, it is not a syncing app. Perhaps if you told us what you are attempting to achieve we can help with a solution.

Carbon Copy Cloner is in fact an excellent backup solution for you. You can choose on the "original" drive only the files and folders you wish to copy (or every file on it) then ask CCC to copy them automatically at regular intervals of your choosing or you can trigger a backup manually when you're ready to do it. CCC has many options but remains simple at its basic level. With CCC you will never have to manually remove files from the backup, a procces prone to mistakes.

CCC can clone the entire startup drive, the one that contains the macOS , and make the clone a bootable drive, something TimeMachine cannot do. It means that in case of problem with the startup drive you could simply use the CCC backup as your "original" startup with no waste of time.

Since you're working with two drives (internal with macOS and external with files) you can easily set up TWO CCC drives, one for each of your regular working drive. CCC can easily backup any number of drives to multiple other drives as long as they're accessible, directly attached or accessible through a network connection (not wifi).

The one advantage of SSDs is of course the speed. If both your working drives are SSDs and your backup CCC drives are SSDs as well you could complete a backup of both drives in minutes, while getting a coffee or even while working. You will notice some slowdown during copy depending on the type of work while you're running the backup chore but not enough to seriously impede your workflow.

I suspect your internal drive is a SSD and I think the Glyph drive is also SSD. I don't know about the LaCie.

However, switching to all SSD, while more expensive, would make work and backup chores would be faster, much faster. Having a bootable, very recent backup will be huge time-saver if your startup drive fails. The SSD speed allows you to make backups multiple times a day if you wish, thus increasing safety.

Your first CCC backup will take more time but all subsequent backups will only copy files and folders that have changed since the last backup. CCC is not an expensive product and is well supported by its maker.

rkaufmann87 asked you what you want to achieve but your answer is not quite there yet. Let's put it another way: what problem do you wish to solve?

Do you want a better, safer backup for your work and archive photos?

Be careful when you use the words "backup" and "sync", they do NOT mean the same thing at all.

TimeMachine backups your drive(s) by COPYING its contents meaning all of your files to a different drive. The process is unidirectional: files only go in one direction, from your work drive to your backup drive. Because the files go only in one direction, if you delete a file in your TimeMachine drive that file will still be in your work drive. With backups files go into the other direction whey they are being recovered. If you say that the Glyph drive is a backup of your 100 000 pictures, it means, according to the definition of backup they're a copy. Where are the "original" pictures? On your main internal drive or on that LaCie drive?

iCloud acts mostly as a syncing machine. iCloud synchronizes various types of specific files among your devices. For example, if your contacts are stored in iCloud, any modification (addition, deletion, update, etc) of the contacts file on any device will spread to all other devices in seconds or minutes. Files go in every direction, back and forth and back again to make sure the same information resides on every device. If you delete a contact on one device, it will disappear from every other device and iCloud itself. That is NOT how backups work.

iCloud does true backups but only for iOS devices, not Macs.

From what I understand from the little information I have, TimeMachine backups are not suited for the type of work you do. Perharps with more and better information about your current issues we can give you appropriate advice.

So, what problem do you wish to solve?