am having Azure Active Directory (Entra ID) and and AzureDevOps organization.
In my Azure DevOps organization, there can be only a single user assigned to the role as "Organization Owner":
How can die EntraRole "Azure DevOps Administrator" be used in order to grant more users the possibility, to act as "Azure DevOps Organization Owner"?
(Otherwise there's a single person doing all the stuff from an organization owner)
Refer to this doc: Create and configure organization FAQs
You cannot have multiple owners for the Azure DevOps Organization.
The role: Azure DevOps Administrator in AAD is different from the Organization Owner in Azure DevOps organization. It will have no full access to manage the Organization.
I suggest that you can add the users to Project Collection Administrators group in Organization Settings -> Permissions. Then the users will have the same access as Organization Owner in Azure DevOps Organization(expcet for recovering a deleted organization).