Groups inheritance
Even though TYPO3 does not limit the depth of backend user group inheritance, it's advisable to avoid complex setups. Typically, 1 or 2 levels of inheritance should suffice. Such flat structures offer significant advantages over more complex, deeper inheritances, including easier maintenance, updates, and verification of the sources of specific permissions.
Note
Avoid complex inheritance within backend user groups. One or two levels of inheritance should suffice and make permissions easier to maintain.