So this is the root of all my problems.
-Messed up handshake for audio
I think I should return my Q900RB while I still have the chance. I don't want to deal with this mess. Also, Samsung's support left me in the air for more than a week about my 5.1 audio issue.
All is not over yet, Craig cunnigham said on 15/02/20 that Q 2019 TV's would have eARC update. Check this video:https://www.youtube.com/watch?v=NMI7nqS61nI
Ths question is now WHEN?
eARC update for HW-Q80R just arrived. No more lipsync problems, uncompressed Dolby Atmos works flawlessly with LG C9. Great!
Last word was May 2020 for 2019 TV soundbar update....but its samsung, so.......
I also got the Firmware update to 1010.5, via OTA using the SmartThings App, for my HW-Q70R Soundbar. Lipsync issues "appear" to be fixed. Still waiting for a Firmware update to bring eARC to my Q80R QLED TV.
Samsung Moderators: The US Firmware Support Download page for the Q80R QLED TV has been broken for a while. The download pages for the HW-Q70R + Q90R Soundbars are also now broken as of today. One can not download the Firmware and perform a local USB update for these devices. Please contact the group responsible for updating the Support Web Site and have this issue fixed. Thanks.