@seb_criteo it is possible to give a user access to configure the content shown on a particular Zoom Room at a Location level today (assuming the Zoom Rooms Location Hierarchy has been enabled and setup for the Zoom account). Note that this function provides the ability to change the content for all ZRs in that Location - it is not granular to the individual ZR. But it is granular to just Digital Signage feature management.
An admin with access to Zoom admin portal > Room Management > Zoom Rooms can visit that page, expand the hierarchy, select the appropriate Location level, then click "[Location] Settings" at the center-ish top. They'll begin on the "[Location] Profile" page. Scroll to the item "Digital Signage Content Admin" and add the user(s) (who must exist in the same Zoom account) by email.
Users enabled in this manner can then see Room Management > Zoom Rooms, the Location(s) they have been enabled to manage, and the Zoom Rooms in those locations, and can manage just the Digital Signage feature of those Zoom Rooms.
Also, as soon as the end of this month, or possibly in October, an alternative configuration method (which I recommend) will be available. Instead of setting the administrators in the Zoom Rooms Location Hierarchy Location, it will be possible to create a User Role in User Management > Roles that provides Edit access to Zoom Rooms Digital Signage, with a Custom Scope that allows selecting individual Location(s). In the medium-term future (few months) this feature will be further enhanced to allow selecting one or more individual Zoom Rooms, or a combination of Location(s) and Zoom Rooms.