How do I connect from one VM to another?
VMs, even within one account, are isolated from each other. There is not a "private network" which connects them.
Some of our users use Tailscale to
create a virtual private network to connect their VMs. Tailscale
allows for exposing SSH (see the docs,
it requires tailscale set --ssh), which operates independently
of the SSH access provided by exe.dev.
You can also connect via SSH, either by forwarding your SSH agent connection or creating additional keys and registering them to your account.