stop trying to use the system python for application development. You will break your OS and you will make your code machine specific. Go read up on Virtual Envs , you were the problem here.
As programmer you should be confident that your code works but for an business you need more than that, you need to prove the code and the assumptions you make with it so that it is safe to rely on.
Good programmers understand that tests allow them to move on safely to the next thing, as professional if you are not doing this you are creating technical debt.
It feels like your analysis is based on having to add tests without enough support from a skilled tester who is empowered to drive testing, if the tester is just told to rubber stamp code without delaying deployment they wont be able to do much. Thats not really the fault of the tester that is a choice to deprioritise test.
As nerds we tend to only look at the specs and get bored when it comes to how the product is marketed and supported but this is a huge factor in development of these products. If they don't have clear obvious use cases they will be much much harder to sell. We are maybe 1% of the marketplace, the difference in revenues between 1% market coverage and 90% is massive, hardly anyone can run a business making perfect products for 1% of market
yeah this is a autopilot problem which comes from the fact that in car electronics are universally badly engineered. Just have a look at any talk about automotive security research.