There was, and then some guy put it to the test á la mythbuster style. I’ll leave the conclusion for you to enjoy

I wouldn’t be surprised if it didn’t get WatchOS 11. In fact, I think the Series 4 and 5 will be considered obsolete next year since they are using basically the same SiP.

I noticed the same on my Series 4, which, as old as it is, used to last me through the day with about 30% left by 8pm. I had to turn on the low power mode yesterday at noon with around 60% and then it died by 7pm