Microsoft 365 features that help users manage their subscriptions, account settings, and billing information.
Hi Eev80,
Different from SharePoint Online or Exchange Online, there is no specific Planner admin role in Office 365 for Business. In Office 365 for Business, we have the following admin roles. Global admin is able to manager the Planner services for your tenant. To learn more, see Microsoft Planner for admins. If you want another user to manage Planner services, you could assign him Global admin role.
Meanwhile, if you really want to have a specific Planner admin role which can be assigned to other users, you may submit the feedback via Planner Uservoice, It's the best way to let the related team hear your voice.
Thanks for your understanding.
Tim