High stress every single night

Verify with another watch if you don't believe in the 265.

My sleep heart rate and HRV seem fine.

I do believe that it’s correctly reading my heartrate. My issue is that it doesn’t learn what is a normal heartrate FOR ME. My normal heartrate is elevated, most likely because of medication I’m on. So it constantly thinks I’m stressed, not sleeping well, etc. And all those features become useless to me.

It makes no sense because the watch automatically calculates my heart rate max (based on actual runs) as far above what it is supposed to be for my age, and calculates my zones for exercise accordingly. My max heartrate is more than 20 bpm higher than is typical for my age based on Garmin’s own calculations. So why doesn’t it adjust its calculations for resting and sleeping heartrate too?

As far as it using an “objective” standard of what constitutes stress, medically there is no such thing. It’s just plain scientifically inaccurate to pretend that there is. I have been seen by many doctors, including cardiologists, and my heart is very healthy. So Garmin shouldn’t decide it knows better than doctors what is “healthy.”

OK then don't rely the readings from the watch since its not a medical grade.

The watch works for some of us as far as I know.

The stress score is calculated based on the variation in heart rate and not just its absolute value. See for example All Garmin watches use heart rate variability (HRV) to calculate your stress level

 So maybe the watches does not show a meaningless result.