IOS apps is configured to access the openhab server using https with an official domain name.
So I would except it to work.
Also look into the IOS App settings, but didn’t find anything revelant.
I don’t use iPhones but have a Mac for work and one must give permission to each application individually to access the microphone. Android works the same way but it will usually ask to grant the permission on the first attempt to use it. Maybe iPhone work the same?
As said, I take a look on the setting to verify the access right.
There are some for the network access, for Siri, notifications, Background task.
But nothing about microphone.
I know that generally application need to tell in their manifest which type of permission is need.
Perhaps it is missing inside the IOS apps ?