I want to know if there is a way to set a co-owner of dataset by default.
or if not set dataset's co-owner in bulk.
What's your use case?
I assume it's something along the lines of, you want two owners so that if one of them is on holiday or leaves the company, or a dataflow falls over, multiple people can administer the data pipeline.
Best practices would be to set up a service account [email protected]_company.com and then set up an email distribution list or shared inbox for that account. you could have multiple service accounts for different departments.
You can use the Excel Addin https://app.domo.com/labs/domooffice/admin/domoadminsetup.msi to perform many bulk administration tasks.