I have a main router Huawei(HG8145V5) from my ISP and AXE75 as secondary router wired connected. Both devices have gigabit ports and they are conected with a cat 6 cable.

The main Router provides the paid speed of 500 Mbps. My desktop connected to one of the LAN ports of Huawey gets around 400 Mbps(there is not problem to get at 500 Mbps), But if I connected my desktop to one of the LAN port of the second router AXE75, It gets around 250 Mbps - 275 Mbps. It is the max speed that gets using second router AXE75. Using a cat 6 cable to test network speed.

Any ideas what is going on?