This issue of missing artwork on your iPad is different to your original issue of missing Qobuz data, so I’ve split out these posts into a new Support request.
In order for Roon’s @support team to better assist you, please provide a brief description of your current setup using this link as a guide.
Make sure to describe your network configuration/topology, including any networking hardware currently in use, so they have a clear understanding of how your devices are connected. Thanks.