I replaced a soundbar with a new Q70R and I immediately experienced the random disconnect after never having it happen over 5 years with an older soundbar.
Apple TV -> Q70R -> Vizio TV
The anynet and power resets did not help. I believe I've solved the problem. My Vizio tv's "system" preferences has an option for CEC. The choices are Disabled, ARC Only, and Enabled. Switching to ARC Only from Enabled seems to have fixed the problem.
disclaimer: I don't k own if the Samsung soundbar supports CEC and the vizio menu notes that ARC Only is for plug and play Vizio soundbars.