Apple watch bricked after full charge (5.2.1 OS)

I have an Apple Watch series 3 aluminum. No issues with the watch until I updated to 5.2.1. After updating, I wore the watch all day with no issues. When I went to charge the watch in the evening (on an Apple factory brand watch charger), it looked different at charging (shows a small symbol of a red lighting bold at the top of the watch screen that would eventually turn green). I never received the usual big green display you see when charging the watch. After a full night of charging, it showed the red lighting bolt again, and would not show anything else. I couldn't operate anything on the watch and it would not respond to a reset, a forced reset, or unpairing it via the app (since it was no longer connected). I sent it back to Apple to fix. They sent a replacement watch. I wore the replacement watch one full day and same thing just happened. Using a different (but still Apple charger). I assume this is an issue with the software? Anyone else have this issue? My watch is under warranty, so I could go through the whole replacement process again, but I am traveling for business for the week and hate not having a watch all week. Anything I can do on my own to solve this?? I am running Apple Watch software 5.2.1 and apple iPhone software 12.3. Thanks in advance for any help/advice you can offer. Super frustrating!