How to access Journals from iCloud.com
There is no way to directly access your Journals from iCloud.com, no. However, if you publish a Journal you can choose "Add to Home Page" (iPad and iPhone), that way if you have multiple Journals a visitor can navigate to your "Home Page".

A visitor would still need the unique link for at least one Journal even with that option selected. Alas, there is no "icloud.com/user/" link one could visit directly.

I don't think it's designed to be a landing page. It's more to generate a unique link for sharing said Journal.