I've set the dpi to 200 in build.prop and HDMI output to 1080p 60Hz. Only thing I've tried is enabling HW 2D GPU decoding in developer options, but that made no difference. Might try 1080p 50Hz instead of 60Hz. The issue seems to cause frame drops but doesn't affect audio at all.
It seems like a part of OPI+ boards does not work with LAN on Android distributions: I've tested Beelink and Tronfy preparing SD card many times and the result is the same. Other interfaces like USB, OTG, HDMI, etc. work correctly in my case.