Thanks for taking the time to write this up and it's quite illuminating to see how poor some of those cables are. I too have run into cables that LOOK like their quality made with built-in ferrites on both ends, etc. only to find their crap. I wish we could find a reliable source of "RF tight" cables that both consistently good and aren't outrageously priced.
Anyway.. I look forward to your results on the OrangePi to see if it's any better. Btw.. why the OrangePi vs. say a Tinkerboard or a Pine64 or other? There are SO many SBCs out there now but it's impossible to beat the community and support found with the Raspberry Pi boards.