@ WujcioPafcio What do you mean you couldn't find the 918? You have a serial port added to your VM so on boot, watch the console (click on the console in the upper right, not the one on the left side panel) . Once it has booted up, the IP address of the machine is listed a few lines up. Should tell you exactly where it is. You are also installing the virtio drivers, so use the virtio network device - not e1000. If the 3622+ runs, the 918 should as well.
The 920 requires you to manually do the device tree map (complicated process, and not automated - you have to do it), and you can't add drives that aren't there later is my understanding so it's not a really good choice. I would give the 918 another try, with the serial console open on boot and scroll back a bit to see what the IP assigned is. I have found the method of using the find.synology.com less than reliable when trying to find a new install.