Chrome stores your bookmarks locally in a hidden system file. You can manually copy this file to create a raw data backup. Windows Location
For a point-in-time snapshot that sync cannot undo, you will need to back up a specific file: the file. backup bookmarks in chrome
If you don't want to worry about manual files, enabling Sync is the best approach. This saves your bookmarks to your Google account in the cloud, making them accessible from any device where you log in. Chrome stores your bookmarks locally in a hidden system file