How to create SQL Server backup from Windows Server to Linux Client with SQLCMD?
the backup is done by the sql server process in a place reachable from the server.
the options usually are:

a local path
a networkpath (like a samba or cifs share)
an cloud storage

So what you are asking can't be done in the way you want.
As alternative you can script the content:
https://docs.microsoft.com/it-it/sql/ssms/scripting/generate-scripts-sql-server-management-studio?view=sql-server-ver15
Schema and data.