Hello, Vladimir. Thank you for this detailed feedback!
The current BRCK is only compatible upto 3G and we are making the BRCK V2 4G-compatible.
The observation of the WiFi freezing as the car moves: this is a function of the existing communication infrastructure - cell phone signal strength depends on the distance to the base stations and if a device is moving (like, say, a BRCK) sometimes it might not be able to modulate its own connection strength fast enough.
Does this clear things up?