There is no functionality for what you want to do. I have also asked the question, and it is a reasonable request, but I would not expect a favorable outcome anytime soon. You should be able to designate other people to access the HA functionality without handing out the "keys to the kingdom" via core router functionality, but there is only one app, and it functions exactly for the intial account holder identically how it functions for those who have been invited to share control.
From the responses you are getting, they don't seem to grasping what we are asking for. What we are asking for essentially is a completely distinct app with limited or limitable permissions at the connected sensor/device level.