IP forwarding and routing on macOS

I have Tailscale configured with two macOS machines; the target machine is configured with subnet routes. I can see the route(s) in netstat -rn on the client machines with the correct Tailscale interface. When I connect to an IP in the routed subnet from the client machine, the traffic is correctly relayed to the target machine, but is not forwarded onto the actual IP address.

The actual IP address routes to another interface, and there are routing rules that exist for it on the target machine.

# example target machine
tailscale up --accept-dns=false --advertise-exit-node --advertise-routes=

# example client machine
ssh # terminates on and never forwards to

Am I missing something? Is there an IP forwarding configuration I need to complete? I attempted to configure port forwarding and/or adding routes with no success.

sysctl -w net.inet.ip.forwarding=1
sudo route add -host -interface utun0

Possibly related - userspace-netstack-mode - not sure about how this works with macOS.