> If social media adoption was driving the increase in suicides, we would have started to see a rise in suicides around the early 2000s, reaching it's peak around 2008.

I think there is a logical fallacy here. Social media has not remained stable since 2008. For one thing, 2008 social media used the chronological timeline. For another, it didn't show "recommended" (or sponsored) content in your feed. There was no TikTok. Facebook was relatively new and MySpace was not even really feed-based as I recall.

Facebook moved away from chronological timelines as default in 2011. YouTube added "recommended" videos tab in 2007.