Sometimes, a Windows OS user has, with BB not running:
Moved the “BraveSoftware” folder to another location.
Quit everything and restarted the PC
Started Brave Browser
Found the “Bookmarks” file in their Profile (usually “Default” folder) within a sub-folder of the “BraveSoftware” folder . . . and copied that to their new “Default” folder.
IOW, if you remove the “BraveSoftware” folder, then, with the subsequent startup, Brave builds a whole new “BraveSoftware” folder.