A small UI tweak that I think would be useful is to add “My Posts” to the “My Activities” menu. That way I can get a concise view of just posts I authored/shared.
There’s already an issue with discussion on github, see https://github.com/diaspora/diaspora/issues/7471
If you want a stream only of posts you authored or reshared, which seems to be what you’re saying, just click your avatar anywhere you see it. You’ll be taken to your profile page, which contains a list of posts you authored or reshared!