Samsung Soundbar S700D disconnects from Samsung Q80D TV

[Saxony Snow]

TV is Q80D 2024 model, soundbar is S700D 2024 model.  Every time I turn off the TV, it loses connection to the soundbar when I turn the TV back on.  The ONLY way to reconnect the soundbar is to unplug it, then when I turn it on it connects again. Samsung customer service have remotely performed every trouble-shooting solution they can think of over the past 2 months and even sent someone to replace the main board. Problem persists so now they're insisting it's an issue with the soundbar.  But I've purchased 4 soundbars so far and all have the same problem.  The first 2 soundbars were S60D - I bought the same model twice because customer service said the problem was the soundbar.  Then purchased two S700D soundbars with subwoofers, again same issue.  I've updated the firmware, factory reset the tv and soundbar multiple times, and used multiple HDMI cables.   Any suggestions? 

Update:

Samsung sent out another technician who replaced the main board and the wifi connector. Problem persists.  

Is there anyone out there with this model tv and this model soundbar? 

[Kev55]

My Soundbar does this every now and then also, make sure your HDMI is a high speed 2.1 cable if you haven't done so already, also make sure it's in the eARC HDMI port in the TV however I'm sure Samsung would have done that if they've been round.

[Saxony Snow]

Thank you for your reply. I just ordered 2 new different HMDI cables from Amazon that will be delivered on Thursday.  Hopefully it's as simple as that. However, is there a specific brand or specs other than 2.1 that you'd recommend?

These are the ones I purchased. 1 is $13, the other is $18. Not sure if there's any real difference. 

Micro HDMI to HDMI 2.1 8K@60Hz, Micro HDMI Supports Ethernet, 3D, HDR and eARC

And

8K 4K Micro HDMI to HDMI Micro HDMI 2.1 Adapter [8K@60Hz, 4K@120Hz] 6K, 5K, 48Gbps, HDR, Compatible for Samsung

[Kev55]

That sounds like you've got really high spec HDMI cables so I don't think you could do any better, hope you get it fixed

[Saxony Snow]

Great! Thanks so much, I'll let you know if they work. 

[Saxony Snow]

Thanks again for your suggestion. Unfortunately neither of the new HDMI cables made a difference, so Samsung is sending another technician out.