apple watch 5 crash

I have a new (month-old) series 5 watch that repeatedly crashes -- at least 2 or 3 times a day. Several times I've happened to be looking at the watch face when it crashes -- in those instances, I've seen different things -- On one occasion, what looks like a lightning bolt next to the time. On several occasions, what looks like a lightning cord leading to a power outlet. I take these to indicate that the battery is low. And the only way to restart the watch is to put it on the charger; it then restarts without my doing anything else. However, the battery is not low -- on several occasions, I've checked the battery level as little as 30 minutes before a crash and seen battery levels over 75%, and after more than a few crashes, I removed the watch from the charger after only 3 or 4 minutes and it shows a battery level well over 50% (as high as 85%) -- and then runs just fine until the next crash.

I've reset the watch and re-paired it with my phone. Thinking it must be an app conflict, I've tried running the watch with only the stock apple apps installed. While I don't know enough to make sense of the watch diagnostic logs, I do note that there's a log entry with the file name "LowBatteryLog..." that includes a timestamp within a minute or two of the most recent crash. I've put that log here in the additional text box -- perhaps it's useful information. I also find multiple ReportCrash log files in the analytics data on my phone.

One final point -- I was having similar issues with a series 4 watch and decided (perhaps too quickly) that the problem was a failing battery.