Problem
The Centralized Pricebook GL Account Management feature is greyed out due to insufficient permissions.
Solution
Follow the steps below to solve the issue.
Enable Enable Advanced Settings permission
In Enterprise Hub, go to User Management.
In the side panel, click Roles.
Find the Administrator role.
Scroll to the Centralized Pricebook.
Select Edit Advanced Settings.

Click Save Changes.
For more, see Manage GL Accounts in Centralized Pricebook.