@JevJeff 

Hi，

Is the Deco on the access point?

And the two Deco M4 are connected via Ethernet backhaul, or wireless backhaul?

How much speed you could get exactly from the M4, both via Ethernet and wireless connection?

Please also make sure the QoS is setup to standard and no device is setup high priority;

Thank you very much and wait for your reply.

@KRISHNA143 

HI,

Have you checked the Ethernet speed from the main Deco M4?

If possible, please draw a simple picture of your network topology, like ISP modem router—main Deco M4(AP mode)? Is there any network switch in use, if yes, how about the model number?

Have you changed a different Ethernet cable to test the speed again?