It directly competes for some use cases, for time, and for ads. One person's total time spent watching videos doesn't grow just because there's a new platform on the block. Kids even use TikTok as an alternative to Google searches for knowledge. I'm not saying TikTok alone can wreck Google, but YouTube at least felt threatened enough to make something similar called Shorts.

IDK about the social network side. Google doesn't really have one, so it's whatever.