I have been struggling with this.
If you are an 'Explainer', then Please explain/comment/opine/discuss on the following navigation disparity.
A user logs into their office.com tenant using their domain account, and they have a full app launcher experience.
When a user selects the "SharePoint" app from the App Launcher tile, they are directed to the "SharePoint Home Screen" which is the new Modern landing page for Modern site creation, with News and sites that you are "Following".
The URL for this landing page is: /_layouts/15/sharepoint.aspx
Any sites that you have "Followed" show up here as well as "Featured" sites that an Admin has added (Edit)
These 2 types of sites are both created using the prefix of "/sites/" or "/teams/" or whatever their SharePoint admin tenant setting "Site Creation" has been modified to, from inside the SharePoint Admin console.
https://[tenant]-admin.sharepoint.com/_layouts/15/online/TenantSettings.aspx
A disparity in Functionality, URL and Navigation
The new Modern UI sites that are created in the above scenario are terrific, but there is a huge disconnect with the default SharePoint sites.
1) Do not show in the SharePoint admin console on the right >
2) Are NOT supported to open and customize in SharePoint Designer.
3) They do not show automatically in any site navigation,
including the standard SharePoint site nav.
including the standard SharePoint site nav.
4) Only these Modern sites are surfaced in the Graph and Delve.
The Standard SharePoint sites, at the base tenant [tenant].sharepoint.com have a totally different Site Creation mechanism.
To create a SubSite in here, you choose +New from Site Contents
Standard SharePoint sites have a Fully Customizable UI and can open in SharePoint Designer.
You can program the SharePoint home page as the starting point