What was done.
a. As with many large, high traffic sites, it served web pages via a cached pre-renderer. The version shown to people and the version shown to Google were different. That's fine. It's allowed. As long as the difference is only to make the page more crawlable by Google. But in fact, it had become LESS crawlable and Google wasn't able to see much of the content. Hug mistake.
b. Gone are the days, where pages can be keywords optimised to gain rankings for those keywords. The page needs to be the most useful in its niche to be top ranked. Content is important, but so is tone, design, depth of detail in the topics covered, variation of display etc. I devised a new design aimed at ensuring people really loved to read the content.
c. Links! Are always needed. I managed a massive outreach which included gaining links from more than 300 Universities.
d. Content. I managed a team of 30 writers, researching topics, editing work, optimising content to gain rankings for the topics that mattered.
e. I managed the SEO engineering team to ensure all parts of the site were best in niche from a technical perspective when it came to SEO. I was the PM to a team of 6 engineers.
The result? A 400% increase in traffic from 400k per month to 1.6M per month.