I just spoke with support for an hour trying to understand their timeframe for fixing all the bugs (Google Assistant lag, etc) and was unsuccessful. If there is a release schedule for updates they wouldn't communicate it with me. So just a heads up, don't hold your breath.
Return it - FW bugs should have been fixed by now - JBL definitely had enough time pre-release.
You are now a JBL Firmware test Guinea Pig
The 2016 Mi Box era S905X based chipset in that soundbar is not exactly cutting edge and that is why it's laggy & slow with Google Assist.
Return it.