I have not found a way to get this to work either. MS have published some articles on this. I have found that you can hide users from SharePoint if you hide them from the address book as per the below article but no solution for guest users.
13 votesthinking about it · AdminSharePoint UserVoice Admin (SharePoint UserVoice Admin, Microsoft SharePoint) responded
Thank you for your answer! The default behavior when you search from a site, is that you get results from that site. You can change the scope to be all of SharePoint by clicking the SharePoint link that’s directly above the search box on the search results page. After changing the scope you’ll also see results from your on-premises content that has been pushed to the Office 365 index.
We’re thinking about whether this default behavior should be different, and are interested in hearing what people think about this.
I think there are two things here. The Site Admin should be able to choose whether site search defaults to the Site, the hub, or even the tenancy. There also needs to be some provision to set a result source which doesn't seem to work against the modern experience. This would mean that certain results could be excluded when a user does an Organisation search. For example, only staff could be returned in the results search.
906 votesworking on it · AdminSharePoint UserVoice Admin (SharePoint UserVoice Admin, Microsoft SharePoint) responded
This was just demoed at Ignite 2018 session BRK2136. Read more about it : https://techcommunity.microsoft.com/t5/Microsoft-SharePoint-Blog/Build-your-modern-intranet-with-SharePoint-in-Office-365-Ignite/ba-p/255453
Hi guys, can you let us know when this will hit general availability? We are particularly interested in the search across org scope which seems to be available by default at the root site level whereas other site collections are scoped to site collection search by default. I think this is a key feature for Intranets based on modern SharePoint architecture. Any update would be appreciated.
Navigation on mobile really doesn't work well... You have no option to go back to the hub site home, and if you add in the standard quick launch navigation on a site to get round this, you see a recycle bin URL, but only on mobile...
308 votes15 comments · SharePoint Administration » SharePoint PowerShell · Flag idea as inappropriate… · Admin →
66 votesin the plans · AdminSharePoint UserVoice Admin (SharePoint UserVoice Admin, Microsoft SharePoint) responded
We are planning to provide a path selection mechanism in the new admin center, but until then we’ll look to at least amend the PowerShell (note that you can already set the path using PnP PowerShell – specifically, the New-PnPTenantSite cmdlet).
974 votesworking on it · 116 comments · Sites and Collaboration » Modern Pages · Flag idea as inappropriate… · Admin →
3,308 votesworking on it · AdminSharePoint UserVoice Admin (SharePoint UserVoice Admin, Microsoft SharePoint) responded
Thanks for your feedback! Just a note to let you know that we’re building your suggestion now. We plan to increase availability to this feature throughout 2019.
Corporate lifecycle is a real and constant pressure in business, often resulting in a need to rename the Office 365 Tenant. To that end we are working on the solution to change the SharePoint domain URL (contoso.sharepoint.com renamed to fabrikam.sharepoint.com). This capability will also then enable the renaming of an individual site collection (contoso.sharepoint.com/sites/abc to contoso.sharepoint.com/sites/xyz).
While we don’t have an estimated delivery date to share at this time, we’ll update your suggestion with details as they become available.