Update 02/02/21: After several months of testing, I now know that it wasn't the charger, outlet, or cord that wasn't charging the watch adequately. The fault lies with my family member not having to unlock the watch and leaving it in locked mode due to too many passcode attempts (probably because their watch rubs on clothes too many times without successfully unlocking for a while). This lock mode seems to consume a lot of power, so the clock quickly drains. Sorry for the late update, just…