I think there’s a misunderstanding here, or I’m not understanding the point being made. Roon Core does not “need its database to be on the same storage devices as the media”.
Roon Labs certainly do strongly recommend (for good - read snappy - performance) that the Roon database is held on an SSD, rather than a spinning hard drive. The media files can be held elsewhere; on a separate SSD or HDD, or external to the Roon Core device, e.g. on a NAS or external USB-attached storage. And if the Roon Core is running on the ROCK OS, then the media files must be held elsewhere - they cannot be on the SSD used to hold the OS and the Roon database.
If the Roon Core is running on Windows, Mac OS or Linux, then the Roon Database will be held on the OS drive (which should, as recommended, be an SSD), and media files could also be housed on the same drive if so desired.