My LG SP9YA Soundbar keeps dropping from the Google Wifi network.
The soundbar contains built in Chromecast.
Here are the details of the soundbar: https://www.lg.com/us/sound-bars/lg-sp9ya-sound-bar
To reconnect, I have to hard reset the soundbar and reconnect it through Google Home.
Is this an internal problem, that hasn't been solved by Google, between the Chromecast installed in the soundbar by LG and Google Wifi?
I did a little digging, but can't find the exact frequency the LG system uses to communicate with its wireless subwoofer. But, many similar systems use a part of the 5GHz band that is also used by some WiFi systems, including Google/Nest WiFi in the U.S. When WiFi devices are close to the soundbar (which is transmitting to the subwoofer), interference can cause issues between those two uses of the same frequencies, even when both devices are following the rules for that band. This feels like it may be caused by that issue, though it could be something else.
Normally, I suggest moving WiFi devices away from the sound bar to mitigate this. But, in your case, it's the sound bar itself that is trying to communicate via WiFi, so that won't be an option for you. I can't tell whether that soundbar supports connecting via Ethernet, but that would be an alternative if possible. If it doesn't support Ethernet, I'm not sure what to suggest, since Google/Nest WiFi only support using that part of the 5GHz band. Using the built-in Chromecast functionality may not work well with a WiFi system that is using the same part of the 5GHz band.