heart rate, sleep score, and steps counter not working

I've had my Forerunner 955 Solar for about two years, but I've encountered several issues after updating the firmware to version 18.15. The watch persistently attempts to update, more than three times a day. Since this update, the heart rate sensor, sleep score, and step counter have stopped working. The "Info" section displays "BMX: 0.0.0. (!)", "WHR 0.00.00", and "Sensor Hub: 0.01". Additionally, the watch no longer connects to WiFi, citing a low battery, even though the battery is nearly fully charged. I have already tried connecting it to Garmin Express, deleting the "RemoteSW" folder, and updating to the beta version, but none of these steps have resolved the issue. It seems to be some kind of update error. Does anyone know how to fix this?