A significant issue exists with managing groups in Portal and ArcGIS Online, especially when dealing with Active Directory (AD) groups. Currently, only group owners can administer groups, which creates serious challenges for long-term management and continuity.
This problem becomes particularly evident with AD-linked groups:
Allowing Admins to manage groups without being members would solve this issue, improving efficiency and reducing administrative burdens. It would ensure that content and group structures remain intact even when ownership changes, making group management more flexible and reliable.
It looks like this is by design, as another post from 2021 (Esri Community post) is stating the same with no change since then. For me it is also difficult to understand that this hasn't been improved since then.
It is really a must-have feature for an enterprise software to administer content and AD/SAML, etc. groups