WAX206 Fast internet wifi, slow LAN wifi

[zwbx336]

I have two wifi 6 PCs, and a wifi6 router wax206. My internet is 500Mbps.

Both PCs are connected with wifi. I tested internet speed using Speedtest, both devices can reach 500Mbps.

Then I tested LAN download speed using 1. LAN Speed Test, and 2. manually sending a large file between the two PCs. Both methods show only ~200Mbps.

My problem is similar to this https://www.reddit.com/r/Ubiquiti/comments/17o2zid/slow_lan_download_speed_on_wifi_devices_what/, but I haven't found an explanation or solution.

[zwbx336]

-- update --

It seems to be caused by wifi connection. I tested the ethernet connection on one/both devices, and the speed is about 300(write)600(read) for one ethernet connection, and 800(w)900(r) for both ethernet connections.

I further searched about wifi lan speed and found that lan speed is more complicated than wan speed for wifi connection considering the signal strength and the router performance.

Any suggestions on better routers that can handle high lan speed via wifi?