@terziyski I believe that the problem is not in the cable, the problem is not with the WAN, the problem is in the correct detection of the speed by the AX12 router, because under the same conditions...

I can't do this because isp equipment is located in the entrance.

When connecting the ISP ethernet directly to my PC (without Archer AX12) with a category 6, 5e, 5 cables, it reaches 500Mbps Similar problem: This post Changed the cable, Forcibly enabled the...