
Explanation:
Register applications:
Setting this option to No prevents users from creating application registrations.
Restrict access to Azure AD administration portal:
What does this switch do?
No: lets non-administrators browse the Azure AD administration portal.
Yes: Restricts non-administrators from browsing the Azure AD administration portal. Non- administrators who are owners of groups or applications are unable to use the Azure portal to manage their owned resources.
What does it not do?
It doesn't restrict access to Azure AD data using PowerShell, Microsoft GraphAPI, or other clients such as Visual Studio.
It doesn't restrict access as long as a user is assigned a custom role (or any role).
https://learn.microsoft.com/en-us/azure/active-directory/fundamentals/users-default-permissions