I ran into the same error. Works after re-enabling WebRTC in Firefox.

That already exists for trucks in several countries, although only as trial operations.

https://insideevs.com/news/440388/germany-a5-autobahn-catena...

You should be able to find it by navigating to 'Connections > WiFi > Advanced > Hotspot 2.0' in the system settings. I'm using Samsung, but it should be in the same place for all other Androids too.