Hi sns,
You can you this command to backup(export) :
Export-SPWeb <Site URL> -Itemurl <Relative path of List or Library> -path <Backup-path>
And this command to restore(import):
Import-SPWeb <Site URL> -Path <Backup-path>
For example:
Add-PSSnapin Microsoft.SharePoint.PowerShell -ErrorAction SilentlyContinue
Export-SPWeb http://sp16 -itemurl "/Lists/List11" -path "C:\List11.bak"
Import-SPWeb
For more information, please refer to: https://www.sharepointdiary.com/2013/10/backup-restore-export-import-sharepoint-2013-lists-using-powershell.html
And this will help you distinguish between using the command in different situations: https://edanan.wordpress.com/2012/05/21/export-spweb-the-url-provided-is-invalid/
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