I am seeing the same problem. Note that it is restricted to APFS volumes. Disks formatted as Mac Extended are visible on desktop and in sidebar. Interestingly, an external disk formatted as APFS which is a Time Machine repository is visible in both areas.
I have reported this to Apple.
UPDATE: I have found that this affects APFS volumes created in earlier version of Mac OS (not sure how far back). Erasing and reloading the disk makes it visible. so, possibly related to a change in APFS code introduced in Ventura. I have erased and re-created several volumes and in every case they are now visible both on Desktop and in finder sidebar.