To create, edit, and manage processes, you must be a member of the Project Collection Administrators group, or have the corresponding permissions Create process, Delete process, Edit process, or Delete a field from organization set to Allow.
By default, only Project Collection Administrators can create and edit processes. However, these admins can grant permissions to other team members by explicitly setting the Create process, Delete process, or Edit process permissions at the collection level for a specific user.
Here is the document you can refer to .
Update :
You can't import or define a global list as supported by the Hosted XML and On-premises XML process models. To learn more, see Define global lists.
The Inheritance process model doesn't support global lists.
This is stated in this official document.
In addition, migration from XML to Inherited is not supported on Azure DevOps Server yet. Please refer to this case.