Curious about this. I’ve an iPhone and iPad. When I want to use the phones cell data connection in lieu of non existent WiFi, Apple lets my iPhone become a hotspot. There’s an On/Off switch in Settings. I have to have BlueTooth On for both the phone and tablet, the tablet then seemingly uses BT as the connection to the phone.
This is not the phone functioning as a WiFi hotspot - I.E. my laptop which is WiFi only, so no BT, cannot connect, as far as I’m aware.
Any thoughts on how this is different ?