Today I discovered a new wrinkle with Garmin data gathering on my Venu 3. I had been quite dissatisfied with the watch reporting via Connect since the last couple of updates, since it didn't seem to track my own experience and data I was getting from my Oura ring. I was trying to get a better handle on my steps per minute and realized I did not have Auto activity start enabled. After setting this up I noticed a few interesting changes overall. My battery life had been about 5 days remaining, but that went down to 3% after one day. My sleep, stress and minimum heart rate had been less accurate since the updates. Now it was suddenly much better.
My speculation is that the watch is not sampling nearly as often when Auto activity start is not enabled. Mostly it is fudging the data based upon a standard one-size-fits-all model with some minimal input from the watch. This does a fantastic job of preserving battery life, but at the expense of data accuracy.