Need to retrieve all previous bookmarks

Description of the issue:
I started a sync chain on her desktop in order to get my mom’s bookmarks from her desktop to her laptop. She had a ton. On her laptop, I downloaded Brave and then went into sync and entered the sync passphrase from the desktop. We went through the sync settings and made sure bookmarks and other things were set up to sync. Both were connected to the internet. Nothing happened for a while. The bookmarks from the desktop never showed up on the laptop. On the laptop, a window popped up asking if I wanted to import bookmarks on the laptop from Chrome. I said yes without thinking. Those really old bookmarks that she didn’t want imported on her laptop and then overwrote all her bookmarks on her desktop.

How do I get her desktop bookmarks back?

Brave Version(See the About Brave page in the main menu):
Version 1.61.120 Chromium: 120.0.6099.234 (Official Build) (64-bit)
I’m pretty sure. I’m not at her computer right now but I believe it’s the currently up to date one.

Type of devices currently running on the Sync chain in question:
Windows 10 desktop. Windows 10 laptop

Additional Information:
Ultimately, the second sync device/laptop overwrote bookmarks on the first sync device/desktop and I need to get the first device’s/desktop’s bookmarks back.

@ktjoj,
AFAIK, Sync does not overwrite data in that way — if anything it should have added the bookmarks from the laptop to the desktop device, but not “replaced” them. Can you please double check her desktop device and confirm that the desired bookmarks are not present still?

@Mattches
I’ve verified. She is missing many of the bookmarks she had before. I will be able to see her devices this weekend. Is there something specific I should do or get more information about while I’m there?

@ktjoj,
Apologies for the late reply — just getting over being sick all last week.

So again, this is not how Sync functions — data should not be overwritten like that, but combined rather. I cannot think of any scenario where those bookmarks would be deleted by adding the device to the chain unless the user manually deleted those bookmarks on one of the devices on the chain.
So if you (or she) was on the laptop for example, and deleted bookmarks there, that change would propagate across devices on the Sync chain.