Apple watch ultra 2 suddenly fails.

I am experiencing an issue with my Apple Watch Ultra 2, which I purchased in April. The watch functioned normally only until few days ago. It suddenly became fully illuminated overnight and drained its battery after being fully charged for less than six hours. The heart rate and blood oxygen sensors are also unresponsive. Notably, the charging process is significantly slower, taking three times longer than usual. On one occasion, I charged the watch to 55% and removed it from the charger. Shortly thereafter, the battery level dropped to 19%.

I attempted troubleshooting as prescribed by Apple’s support, but without success. As a last resort, I reset the watch, which required me to update to iOS 26.

Despite the update, I continue to encounter issues with the fitness features, particularly the heart rate and blood oxygen sensors.

I charged the watch again to 74% and attempted to use the workout app. Initially, the app failed to launch for my run. After restarting the watch, it successfully started my run. However, as I was approaching the 5km mark, the watch abruptly shut down without warning. I have since attempted to charge the watch, but it has not started up.