I have a router running OpenWRT between the Dish and the WAN interface on my MX.
The router has a static route in it pointing back to the dish.
This allows anything on the LAN side of the MX to reach the IP address of dish (192.168.100.1).
Here's what the static route looks like.
Since Starlink started enforcing only one IP address per dish, the router also acts a NAT device, allowing multiple devices, including the MX, to all access the Starlink network simultaneously.