I think this depends on what you want the link to be.
What you see when you click the link is either a list containing your last posts or the drafts you haven’t posted yet [1]. Of course, you can also find other activity in other tabs of that page, but I am not sure I would change the name because you can find other information on related pages. For me, the link in the sidebar is more focused on posts and should help users find what they posted, while there is a general link about your activity in the avatar menu. I wouldn’t want a link to Activity in both menus; having that in one seems enough.
in the latter case, the link should change to ‘My Drafts,’ which currently only works for the “new new” feature ↩︎