User blog comment:ChipFan111/Wiki Feature Help/@comment-44807868-20200408044734

Yes, it does indeed have to do with the UCP. The future of blogs is pending and the article comments are planned to return under a rebuilt state; when exactly the further details and/or release will roll out, we don't know yet.

Edit: Rereading, I realized I didn't address your point quite clearly. You can find the Wiki Features in Special:AdminDashboard on bottom right, but for the moment, there're only three features you can enable or disable: Europa Infobox Theme, Require all contributors to log in, and Message Wall; both blogs and article comments are currently unavailable due to the reasons stated aforementioned.