android auto
First I heard of this, but since it seems to be just some software that runs on the hardware of car manufacturers it seems rather unlikely. But very theoretically possible, if the car manufacturer was using default process scheduling in a CPU constrained machine and now switches to real-time scheduling in an update. But that was possible for years before this news, the code has just been mainlined to the default kernel now. If the car manufacturer cared about that they would probably have done it already with a patched kernel.
Both of these options have their pros and cons, and I think it is important to explain these well to the council if you want to have any hope of convincing them.
A line of argument that has had some success in Europe is what has become known as “Digital Sovereignty”, basically a fancy term for saying government should control its own infrastructure. So you might want to sell it as an easy way to have a permanent archive of public communication and a method for it that is under their direct control, rather than as a way to find more engagement.
As others have said self hosting has a maintenance and moderation overhead, but this can be lessened by running an instance together with other cities while still retaining most of the benefits of self hosting.
Seeing from the linked cross-post that this is about Port Alberni, and considering that http://portalberni.ca/ returns an empty reply while https://portalberni.ca/ lets me know I have been geoblocked because I’m outside of Canada and the US, I’d say you have an uphill battle before you though. These people made a website (probably paid for it, too), and then killed much of its use by geoblocking most of the world.
Good luck.