Kroaler, you send pretty excited about your dream and also unsure where to begin. I'd suggest you separate your research into 3 areas, production, business administration and social capital. You will need all 3 to be successful. It sounds like you are familiar with production methods and have ideas for improving on those. That's good. Running a business is an entirely different skillset. Think of this as the business of business. Social capital is relationships; vendors, customers, banks, staff, contractors, etc. For large scale, low margin manufacturing you will need all 3 in spades. If you want to stick to the automotive industry I'd recommend you use your technical chops to find a niche. Even better if you can build a brand.
I know there are plenty of entrepreneurs making parts for all sorts of vehicles that improve on the originals. With customers acquisition costs so low this could be a very lucrative market. Lisle does this with tools. Dorman does it with parts. My company owns Sprinter vans. There are custom turbo resonators, ECM tunes, fan removal tools, brass overflow line junctions, etc. Something to think about.
For a small manufacturer I'd really recommend trying to deal as directly with your customer as possible and building a name with those customers. With the interest in artisanal goods I think you could find some very interesting markets to serve.
I remembered this article when I read your post:
https://www.nytimes.com/2017/09/03/us/quillen-small-business-michigan.html .