noticed it myself with the keyboard connected and it not going to sleep.
found the tablet hot when i went back to it which suggested the screen remained on and drained the battery.
only had one update from the android end of it since i got the tablet.
like yourself the sound is weak , not ideal with background noise. apart from that i use a cheap Bluetooth speaker when at home, which will only further drain the battery.
i found from the android end , if i disconnect the keyboard while the machine is on the volume rocker sometimes doesn’t work and i have to go to settings to control the volume. the tablet seems to not recognize the keyboard disconnected or something. not a major deal really.