Thanks for sharing your detail review about SteemX.
Basically, SteemX is still under development, currently around 40% complete. What you are seeing now is more of an early preview than a final product. Many features including comments, communities, and certain navigation elements have not been implemented yet which is why some links or sections might not work as expected.
Your point about the notification feed being cluttered is a good one and we plan to add filters (like replies or mentions only) to make it more manageable. This kind of feedback is valuable to us.
Good to hear that it's still developed. Once ready I will stop by again. Good luck with it.