I guess I’d record it manually but I always have my watch on when workout out

If I wanted to use my Apple Watch in low power mode and disable all the features I paid for I’d rather just buy a Garmin. My series 7 with AOD enabled and a 1h workout barely lasts the day (10% remaining usually). If I turn off all the features I can get 2 days battery but as I said then what’s the point?

Try disable low power mode, enable AOD do some workouts, be active and use your watch throughout the day and I’m pretty sure your ultra will be at around 50%. That’s a more realistic use case.

Here’s the thing, lots of people wear small watches like Casios so there isn’t really a “too small” here.

You could get the larger Watch and have it fit perfectly fine on your wrist. It just depends If you want a larger Watch or not. I personally say the larger is better if it fits but it’s personal preference