Speed test from AiMesh Node to Ookla?

[AndyB21]

I have recently moved my dual-node AX92U network to a wired backhaul (specifically Netgear PLP2000 powerline "ethernet" units) and would like to measure the actual throughput across that link. I was hoping to run the Ookla speed test on the Node to see how the throughput differed from the same test run on the Router, but I haven't been able to figure out a way to get the full gui on the Node. Is there a way to get to the GUI? Or is there some other way to run such a test? (Speed tests run from devices connected to the Node show speeds drastically lower than when the same devices are connected to the Router, so I want to know whether that is due to the link itself or to the second AX92U processing.)