In 2020, I would argue that almost all of SEO is simply best practices.
Google has become so good that the best way to succeed is to just play it smart - make content your visitors actually want to read and put it on your site.
If you want to make vehicle pages, put real content and unique images on them.
Website providers shouldn't be the ones doing SEO, but that doesn't mean they can't. We used to offer SEO packages that were quite effective (back when I felt that there were techniques that could genuinely move the needle in 90 days), but now we just audit the sites and provide suggestions to the client without it being an "SEO package". Their success is ultimately our success, so it would make no sense to help one succeed over another.
In my experience working with Automotive SEO vendors, 100% of them were either keyword stuffing, making useless blog content or stuffing backlinks to our site. We tracked everything in https://www.gshiftlabs.com and had to call them out on their seedy forum spam and offsite garbage that they didn't even tell the dealer they were doing.
You and I discussed gShift (Canadian group) in length, I do believe. I used them for close to 7 years, exposing similar results. It was easy to do and pathetic on the part of what groups were promising and providing via "SEO." I still don't think anyone does it as well as them. @craigh