If your DNS is set to CUSTOM1 127.0.0.1#5335 in the settings, and pihole is working, then unbound is working.
I think there's a way to enable logging in unbound, but I've never bothered since it's never given me any issues.
I've been testing this docker container and it's been running fine. The updates seem a bit sporadic, but I haven't had any issues.
In the image you provided, the completed download folder should be /data, not /mnt. If you click on the left arrow, you should go to the parent folder, and see the /data listed in there. Select /data, and you should be good to go.
Rikdegraaff, have you mapped the /mnt/disk7/UsenetDL folder in the SABnzbd docker?
In the example above, you would reference /data to get to the /mnt/user/Downloads folder. By mapping the folders, you don't reference the actual folder path. You can replace the Downloads folder with the path you listed (/mnt/disk7/UsenetDL)
I saw a similar error a couple weeks ago. My error was "/usr/bin/env: ‘python’: No such file or directory." The solution I found somewhere (either here in the unraid forums, or in the Sab forums) was to change the first line of the "sabToSickBeard.py" file
old:
#!/usr/bin/env python
new:
#!/usr/bin/env python2
Does your top line have an "\r" in it? If so, you may need to remove it.