Same problem with a TV S95B and soundbar Q700B with good HDMI 2.1 cable. Of course none of the fake advices on this thread helps. This technology is just not working.
I spent hours to try to fix sync, adjusting audio delay on both TV or soundbar, sometimes it almost work with some sources like Netflix on TV but it doesn't on other source like Nvidia Shield Pro. And when you think sync is ok on both speakers, well, you've just lost audio/video sync.
Hey Samsung, I gave you 2000 EUR to get this...
It's a shame that a such advertised feature is just *****