Why are TikTok cookies appearing in Safari settings?

Web pages are made up from content loaded from dozens or hundreds of other web sites, services, advertiser networks, and myriad servers.

Have you noticed the “share on social media” icons shown on many webpages?

Yeah, those icons are often loaded from those providers’ web sites, and will get cookies from those services.

The web hasn’t been one web page served from one web server since roughly Y2K, with rare exceptions.

They are coming from web sites you have visited.

Sites can link to and drop cookies from multiple sites you thing may be unrelated.

It's how your activity is tracked across the internet.

Your question seems to answer itself. Are they not from TikTok?