I understand very well the interest of the hotspot for preconfiguration, OK, but I don’t see what prevents me from using it as a traditional wifi hotspot to access Volumio.
As mentioned in my first post, the particularity of my installation is that I don’t have a wifi network in my home, so I have to make do with the Volumio hotspot. I’m not going to install a wifi router to control only Volumio, it’s an ecological and economical nonsense.
In this case, the fact that the captive portal opens is not an Apple problem, but a behaviour that can also be found on Android or Windows machines (hence the second line for the hosts file). This is because there is no internet connection behind the hotspot.