@OrdinaryButt - I just attempted to install a RealTek 8127 SFP PCIe 4.0 x 1 NIC in my Unraid server (7.3.1) and appear to be having the exact same issue as you. Unraid reports the interface is down, although my UniFi network switch seems like it is ready to go (i.e. no errors or warning from it, once I managed to configure it for normal traffic, instead of as an uplink port ;) ) I was just wondering if you have been able to figure out a solution, yet? Thanks!