Need help understanding TikTok's messaging APIs

I'm integrating TikTok into my SaaS platform and I'm having a hard time figuring out which API I actually need. My goal is: - A TikTok user logs into my platform using TikTok OAuth. - I obtain an access token. - Using that token, I want to send and receive TikTok messages directly from my platform (similar to how platforms like Sambad.io, ManyChat, etc. work). The problem is that TikTok's API documentation feels pretty vague regarding messaging. I can find information about Login Kit, Content Posting APIs,