Hello, I recently got an Archer AX10 as a gift from a friend. I initially used it as an access point, but now I use it as a standalone device connected to a Nokia Media Converter using VLAN ID and PPPoE. However, I have one issue. I always see a device connected to my wireless network. I block it, and then a new one appears. They always have a new IP and new MAC address. No matter what I do, I always see one unknown device on my network. The guest network is completely disabled, and I have also changed the password numerous times. Now I'm at the office, and I logged into the Tether app, and I still see a new device. I block it, and a few hours later, it reappears. In my house, everything is mostly connected via Ethernet. I only have one laptop and my phone connected wirelessly, which I see as devices. What's the case here?

Name : network device
Connection: 5GHZ wireless
Mac Adress : 06-CC-99-AF-B2-83

I tried to ping the device using local ip with no sucess.