I think I didn't express properly what I meant. In any case I've also made some pretty good cars and engines by getting out of comfort zone of fine-tuning sliders until the desirability stops going up, and instead setting up something I think they might like and fixing the rest of it to match. You might be surprised to find that Family, Delivery, and even Utility can be very happy with an I3 tuned for fuel efficiency. I've also done a couple shitbox-oriented (or eco oriented) campaigns. Also, once you get some familiarity up, you can build V12's, and they love those. Since engineering cost is spread across not many cars in those markets, I think that's a much better choice.

For example, early luxury and GT and both well-served with I6 engines, and those have a MUCH faster engineering time than V8's. I'm still sometimes surprised by what works when I thought it wouldn't, or even works better than what I used to be doing. You can certainly find a forumula and stick to it, but trying different things is worthwhile. I disagree that it's quite as formulaic as you think, though. Or, you could check out my Let's Play I linked in the OP. I don't think the game is very hard as long as you have someone to ask questions to, the official automation discord is pretty active. I had a little trouble at first but I learned a lot from watching his videos.

Compny car tycoon game