Ok I miss understood apperently. I can not confirm your issues. I'm using 100m network (my router has not enough gigabit ports). No network lack at all. I can watch TVH 1080p live streams, Amazon VOD 1080p, 4K h.265 files from my NAS. My mediaserver + tvh server is a Odroid C2 running Ubuntu with a usb HDD (so it suppose to be way slower than your setup).
Not sure what the issue is. Wetek Play 2 had strange rare ethernet network failures in official. Maybe something similar here.