Thank you for your suggestions. We are currently working on improving our post performance section of Social Marketing, estimated to be completed by end of October. Social Marketing does pull in historical data and post-performance for posts made organically through Facebook*, Twitter, and Instagram (from the moment it became a business profile) or another social media publisher.
*Due to Facebook API restrictions, only data from the last 100 posts made before the connection date will be reported within Social Marketing.
Regarding adding more platforms like YouTube and TikTok, is on our roadmap as we will prioritise will keep posted. Thanks !