The early Netgear Readynas NV+ (sparc) and 1100 units (4 across) all had a design which must have looked good on paper.
However the buttons that are supposed to push in, and displace a latch upward, allowing the arm to extract the drive typically is frozen. I don't know if they ever worked early on, but nearly all of the original ifarant units and the first netgears, which all seem to be about the same just don't work.
there is a small spot in one of the holes you can stick a small probe into and actuate the latch thru a small lever action.
This video of my unit, while removed shows the actuation. I'll share the raw video, a Youtube video of it, and since I'm not the first one to do this, another illustration for reference.
Disk Tray Removal, Youtube
Raw video (google drive)
A longer version of opening the Duo (and probably the NV)
Here is one of the newer units with a reviewer extracting the drive.
Readynas Duo (at about 2:19, has extract)
An annoying old review of the Readynas 1100 (for reference what one looks like)
Almost feel bad calling it annoying since the reviewer is a Jesuit priest.
Readynas 1100 Review