Coincidentally, I happen to have been reading into SEO more in depth this week. Specifically official SEO docs by google:

https://developers.google.com/search/docs/fundamentals/seo-starter-guide

To be clear, SEO isn’t about tricking search engines per se. First and foremost it’s about optimizing a given website so that the crawling and indexing of the website’s content is working well.

It’s just that various websites have tried various “tricks” over time to mislead the crawling, indexing and ultimately the search engine ranking, just so their website comes up higher and more often than it should based on its content’s quality and relevancy.

Tricks like:

• keyword stuffing
• hidden content just visible to crawlers
• …

Those docs linked above (that link is just part of much more docs) even mention many of those “tricks” and explicitely advise against them, as it will cause websites to be penalized in their ranking.

Well, at least that’s what the docs say. In the end it’s an “arms race” between search engines and trickery using websites.