We really like our Eufy Spaceview Pro baby monitor (Model 8321-M). We’ve had this one for a few years, and the battery life has slowly drained to the point that it shuts off immediately when you unplug it.
About six months ago, I used the trick found on Reddit where you unplug the battery for about 30 seconds and plug it back in. This seemed to give it some additional life, but now the battery is dead. (Not surprising after two years of daily full charge/discharge cycles).
In this video I open up the monitor, remove the old battery and replace it with a new one.
Amazon Page for the Eufy Spaceview Pro
Amazon Page for the battery pack
Reddit Discussion of unplugging the battery for extra life