There is at least 1 (the M.2 SSD on which the OS is installed), and possibly 2 (the extra one being the internal storage on which you can put your music). Based on the screenshot, you have 2.
The one likely at fault is the M.2 SSD on which the OS is installed.
You can replace the M.2 SSD yourself (make sure it’s an NVMe SSD with the right pin layout).
I am personally quite satisifed with my Samsung 980 NVMe M.2 SSD.
The problematic part is that the Nucleus OS is not available for download. Instead, you’ll have to install ROCK and Roon Support can remotely trigger the upgrade of ROCK to Nucleus OS.
Roon has been a bit ambiguous on this topic, as it has both recommended this approach, but also strongly disencouraged it (depending on who you talk to).
If you’re not comfortable, just wait for Roon to chime in. Since you purchased it directly from them, and assuming it’s still under warranty, you might want to let them repair it free of charge.