Changes to administrative accounts should not affect your SSO applications. Definitely worthwhile checking that the Application Administrator is updated as per:
https://learn.microsoft.com/en-us/azure/active-directory/roles/delegate-app-roles
If you're administering accounts utilising the SCIM connector, documentation on updates to this are located here:
https://learn.microsoft.com/en-us/azure/active-directory/saas-apps/apple-business-manager-provision-tutorial