I have some new information from the official reseller of Denon in my country.
The Denon receivers which have been delivered until June are in need of the separate HDMI-box from Sound United. But the ones arriving in late July-August will have a new HDMI-chip in them. This is by no means an official statement I can link, but they are the official reseller in my country so I’d say it’s pretty legit.
This seems to be the case in Australia - if that is where you are, the current Denon x700 series with 'faulty' HDMI chips are available with a discount by as much as $300 AUD in waiting for the new stock.