The properties prefixed with FLOWABLE_ID_APP_ADMIN are for bootstraping the application (creating an initial admin user if there is none). However, you have LDAP enabled and in this case, no users are created. You need to use the users which are in your LDAP to login.
The issue is that for the LDAP users to be able to log in, the users have to be given permission in the Flowable-IDM.
To give the users the permission, I need a default user to log in to Flowable-IDM.