AR750S-Ext Gigabit Travel Router - Too slow

I am using the AR750S-Ext as a router plugged into my home network so I can hand out static IP address in a subnet. NO WIFI enabled. I have the AR750S-Ext ( plugged into my home network ( via the WAN and all the equipment is connected to the subnet via a switch.

I am getting half the throughput when I add the AR750S-Ext into the picture than when I just plug the ethernet cable coming directly from the home network into the switch (I had to change some IP adresses in order to complete the test).

I have no VPN or any other functionality enabled.

Is there something I am missing to improve the Slate’s throughput?

I cannot see image attached. What is the speed?

In the router’s admin panel, in client area, do you see real-time data statistics enabled? If yes disable it.

I am in a rural area. The speed is not great regardless. What is relevent is that back to back speed test with the router in the mix is half of the speed when the router is not in the mix. The real-time data is disabled.