I have the same issue as
Same setup (everything wired) and with iperf3 i get varying speeds, mostly somewhere 1 - 10MBit. If I run it multiple times, sometimes I get lucky and hit >900MBit. But mostly <10MBit.
With autofs this works fine for watching 1080p x264 content, but recently i tried to watch some 4k stuff and it buffers for 1min every 1min.
In the post above it is said, that it may be a “faulty unit from the early days” - I ordered mine very early as well (last email I found was the order update from 10th August 2018).
Thanks for looking into it.
PS: Another thing: the remote stopped working after ~1month of use. I didn’t care much and switched to the Android app. But would be nice to have it working again