Apple Watch Ultra 1 with watchOS 11 / watchOS 11.0.1 has become practically unusable

With the update to watchOS 11, my 2-year-old Apple Watch Ultra has become practically unusable. The battery drain is unbelievable. Initially, it went from 100% to near 0% in 8 to 10 hours, and with watchOS 11.0.1, it only got slightly better:

Within 12 hours – including a 5km walk – the battery lost 85% of its charge!

Unbelievable.

Now, I can only hope that Apple finally fixes the problem with watchOS 11.1. Until then, I’ll reluctantly use my old Watch 7 with watchOS 10.6.