Fonts saying there are duplicates.

Currently running Win10
Im trying to backup everything before formatting and loading Win11. I'm backing up by going to fonts "folder" in control panel, selecting all, copy, and paste into folder on external backup drive. The only thing is that as its transferring, towward the end, it prompts that there are fonts with duplicate names, would I like to overwrite or skip.
How is it the fonts folder has duplicate fonts with the same name (apparently) But when I copy them over, windows wont allow for all fonts, even the duplicates?
What do I do to properly copy/back-up ALL fonts, including ones with same name?

Berton said:

Also note that a folder or subfolder cannot contain 2 files of the exact same name, one has to be at least one character different from the other. Same for subfolders in a folder.

Thats why Im confused. C:\WindowsFont is a folder that stores the fonts you install. If I try to copy the contents from the "Fonts" folder (C:\Windows\Fonts) and paste those into some sort of folder I create on an external HDD named "Fonts". I get that error, exactly for the reason you said. So, If that applies to the folder Im copying it into, the external HDD one, then how did the original folder at C:\Windows\Fonts manage to hold fonts with the same name? Are Fonts grouped together into families or something so long as they're in the original Fonts folder, but if you try to copy them somewhere else, they expand?

Id still very much like to understand this, but for the time being, I simply copied over the entire "Fonts" folder from C:\Windows, over to the External HDD with no errors.