Make a Hotspot that works in a car (Linkzone 2 fails)

[mrmox]

I saw someone else ask about replacing a Linkzone 2 so I thought I would ask a more specific question.
Hope this is appropriate.
Car has an ANDROID HEAD UNIT I want to have it's own cellular connection.

Linkzone 2 with T-Moble seems to work until the car gets too hot.
I am speculating since I cannot find any internal secret log files in the Linkzone 2 that tell why it is shutting off.
(links to Linkzone 2 forums for extreme users would be appreciated though!).

I tried with and without the Linkzone 2 internal battery.

Without the battery, there is NO "autostart on power applied" setting I could find.
(I think Alcatel is dumb for not considering this use case).
So I wired the USB PS to an always-hot terminal of the car battery. Then turn it on with the button.
Still Linkzone 2 shuts off at random, or locks up and I have to cycle the power and turn it on again with the button.

With the battery, it also dies at random and has to be manually powered on with button.

Are there parts here I could cobble together to make something that might work like a Linkzone 2 with auto-start on power applied (which I cannot have)?

Oh yes I set the Linkzone 2 to never turn off.
And I know there are tricks for my cellphone to turn on its hotspot when I get in the car and the bluetooth HFP runs.
But I would like to have something that uses the Android Head Unit and its GPS to track the car.
Cheap! (monthly anyway). T-Mobile is $10/mo for this.

Thank you for your kind attention.

-mrmox