I was unable to convert to DNG

Only Adobe knows when there there will be an update, and they don't usually announce the updates before they're ready.

I don't work for Adobe, and have no access to inside information.

Please understand that this happens every time a new camera is released. The camera manufacturers do not give Adobe information about upcoming cameras, so Adobe has to buy a camera, examine the raw files, and then provide support for it in an update. These updates happen, as far as I know, 4-5 times a year.

So when buying a new camera, it's a good idea to wait until it is supported by Camera Raw.

This page gets updated whenever a new version of Camera Raw has been released.

https://helpx.adobe.com/camera-raw/kb/camera-raw-plug-supported-cameras.html

I have the same issue and although "few weeks" past since Adobe Community Professional's reply there is no solution in sight. What Nikon s/w can be used to process NEF file? Per Berstern - could you help?

The Z6 II is a new camera, and you will have to wait for an update to the DNG converter for support for your camera.

This could take a few weeks, and in the meantime you have to use Nikon software to process the NEF files, or shoot jpg, or jpg + NEF and process the NEF files later.

When the update is released, there will also be updates for Camera Raw and Lightroom, so if you have a Creative Cloud subscription, you will be able to process the files without converting to DNG.