Hi,
I installed an Opensuse 15.4 workstation with kde desktop environment. The default “System Monitor” application does not show all the disks/block devices available on the machine when i try to configure a disk sensor. Only a limited set of block devices is available. Do you have experienced a similar behaviour?
As a workaround I installed ksysguard5 that do not exhibit any anomalies.
If I add a new page and then set up that new page to display disk statistics, AFAICS all the mounted partitions can be monitored, individually. If I plug in a USB drive and mount it then, that drive can also be monitored.
But then, that’s the same behaviour as that displayed by KSysGuard …