Soldato
Yes seen it weeks ago but 1 10Gb port is radically ADSL type isn't it (so not for VM cable use to connect to VM HUB4 in modem mode for example) or am I reading it wrong and you simply use the other port then you can use the left over one for 10Gb/S LAN.
"The RT-AX89X comes with two 10G ports, one Base-T and SFP+ port, which means both fiber and copper 10G connections are supported. Capture ISP advertised speeds or use your own 10G LAN network between PCs and NAS."
Then the SFP+ port not compatible with 1Gb/s.
The SFP+ port is compatible with whatever adapter you put into it. If you put a 1Gbps RJ45 SFP+ adapter in it, it will happily run at 1Gbps. Or 10Gbps if you use that type of adapter. What it can’t ever do is auto-negotiate because the adapters can only run at the speed they are told to.