SPO organisation assets not showing up

We successfully set up a SPO organisation asset library according to this documentation: 

Create an organization assets library - SharePoint in Microsoft 365 | Microsoft Docs

Templates are not showing in "New" menu of our O365 desktop apps (E3 licence present).

In Word they are visible at the start page in a "recommended for you" section so it seems to work partially.

Before we distributed templates using a fileshare and GPO to set workgroup templates.

Could that be a reason?

SOLVED: GPO "Hide file locations when opening or saving files" was in place