I remember one of those on Amazon with like a thousand reviews that were all meme reviews about using it whilst driving. Cant find the exact one, but it was one of those many Amazon products full of joke reviews.
The ergonomy of most laptops (and keyboards in general) is poor. The modern laptop that is most ergonomic is the "2 in 1" design, which can be folded and used as a tablet.
For a programmer, an ergonomic keyboard with a trackball, connected to a 2-in-1 portable in tablet mode, might be easiest to assemble from common components for working during travel.
I had a similar situation to the GP in that I only ever used my laptop in a car for an hour or two a week. In my case it was whilst one of my offspring was doing some sports related thing that I had to drive them to.
Most of the time I'd just take a book to read but sometimes I'd like to tinker with some programming thing in that time.
More often than not there was a nice cafe to sit in, or a nice bench somewhere in the sun, or a viewing gallery that meant I could watch rather than staring at my laptop. But not all venues were the same.
Some had nowhere to watch or nowhere to sit in the warm or dry, and nowhere suitable within a short drive, and so I'd default to sitting in the car experimenting with seat angles/etc to get into a position that wasn't awful.
Not owning my own car meant I was often driving something different each time which added to the fun. (RIP UK Zipcar.)
The keyboard however, is over the steering wheel, and while the arm placement is _similar_ to holding the wheel, it's a bit awkward, typing on a keyboard and operating a steering wheel are just quite different movements.
I _think_ it'd be ergonomic if I had some kind of keyboard and mouse/trackpad solution elevated on my lap, but the steering wheel gets in the way of a standard lap desk pillow thing. It'd have to be split.
For my one hour per week I haven't bothered yet. But I do think I could come up with something that'd have similar strain to just driving the car. Which, yeah, is probably not as ergonomic as a good desk setup to begin with.
I have a "car desk", which is just a little expandable contraption you hang on the steering wheel, then you can place your laptop on it. I wouldn't call it ergonomic per se (the right external keyboard could probably fix that), but using it for about one hour per week, it works well and doesn't cause any issues I'm aware of. The driver seat is not a place where I previously could get any work done, so the bar is a bit low.