I had a similar issue where sound would basically drop off at random times, sometimes after 5-6 seconds and other times it might last a couple of minutes, the glitch would only last half a second or so and the sub would still have sound so the audio was still getting through the system.
The way I ended up solving this (after trying factory reset, trying to locate a firmware update (didn’t appear to exist), swapping from hdmi arc to optical, relocating sub etc.) was to change my source audio to stereo, it’s a 2.1 bar anyway. This solved my audio issue and the sound quality is excellent, it’s just in the bedroom where surround isn’t a priority, hence the soundbar, noting I never had an audio issue on Bluetooth, as a music bar it always sounded pretty good, no audio issues on Bluetooth at all.
