My network currently has 31 devices connected, all via DHCP. 42 DHCP leases have been given, and has always been working fine. All devices are working fine and are connected to the internet.

Problem: I built a new PC using a MSI B550M PRO-VDH WIFI motherboard which uses RealTek wifi & ethernet, and the wifi AND ethernet connection will not obtain an IP address via the Deco X20. Most of the time the ethernet connection in Windows 10 will show that it's an "Unidentified network", and will sit at the self-assigned 169 IP address. Ocassionally, seemingly at random, the router supplied by my ISP will assign an IP, and it'll start working. I do not want this, I want all clients managed by the Deco. This behavior happens for both the wifi and ethernet connections.

What's going on here? Why can't this client get on the Deco X20? There's no software installed on this machine except a few games, so no antivirus or VPN software.

Ethernet clients > TP-Link unmanaged switch (TL-SG116) > Deco X20 in Router Mode > Modem