Sorry, mickyfu, but Drogon is absolutely right. Even a gazillion links to non-existing pages that give a proper 404 won't hurt at all. We personally tested this on a very large scale with an own site, high six digit number of the spammiest links available to 10k made up URLs. 404 nightmare, but zero movement in the SERPs, neither up, nor down. Google ignores those links, Google ignores 404s and 410s. What Google doesn't like is existing, indexed pages often showing errors because of misconfigurations or similar, since they want realiable results.
Then again put your website where your mouth is. I'm sorry but I work on these kinds of subjects. I don't need hear say kids telling me what does and does not work, when I see it with my own eyes and experience. Again, put your websites where your mouth is. If not then keep believing your Charlie Floate blogs.