Good day everyone!
I know it's a long time since the last reply here but maybe this helps to clarify things: 
BMW R1250 RT
 iPhone: 15 pro
hotspot settings: compatibility on
Gs 911 wifi with last update via PC software! 
  - do save the hotspot from main iPhone as described in the instructions. 
  - first connect into D2D mode, I did a quick autoscan ( but I don't think its necessary)
  - activate the hotspot
  - remember to switch the device in infrastructure mode ( little red button one click ). The Gs 911 wifi should connect to it (check leds flashing sequence as explained in the manual).
  - in the app you should see listed your previously known device from D2D mode scan 
  - connect and that's it. 
In the picture below a screenshot from my first test yesterday. Unfortunately my battery was under 12V, so i did not enter the service functions as recommended. will try again later when it´s not -4 C° on the garage.
  I hope this gives a better overview for the hotspot connection variant, which to be honest was my main concern also as my home wifi is not reaching the garage.
Other option:
-Have a tablet / another phone and use the main iPhone as hotspot (wifi internet AP) for both devices. 
 Well, Happy new 2025 to everyone!
PS:
 got two errors yesterday, clear faults and run again, did not came up. We'll see:
Emergency_(Telematics) Module
OxB7F32C internal control module error (F count : 1)
OxB7F30A SIF: General mobile network error ( F count: 3 )
--- Sorry, it is imposible to updload a photo----
https://imgur.com/a/5rNrjAA