"We would lose some interactivity within content cards inside timeline though - for example, a Post card would not display the whole post, but only a Post embed and a sharing comment."

I don't see this as a problem at all and should likely speed the page load up a little. If users see that the post is something they are interested in, they will gladly be willing to click over to it.

So many good ideas here at UNA, constantly bubbling up to the surface... Thank you, Team, for working so hard day and night.