I am using gentoo on kvm, and I have configured it so that it connects to the gateway, but I do not have internet connection. In the gentoo VM, I have internet access when using my host for connection, but not whonix. I had issues connecting when using a kali vm as well, but I forget what I did wrong and/or how I fixed it, so I might be missing a step.
I also checked, and I am connected to tor on the gateway, and I can connect using the workstation as well.