Apple Watch 3 activity rings inaccurate

I have had version 3 for almost three months. I previously had version 1 and the activity rings were much more accurate and consistent. Some of the issues I have had are-

when I get the reminder on the stand ring, I can get up, walk briskly for ten minutes, climb stairs and it does not register any activity. But sometimes I get the reminder and it will say I did it when I haven’t even stood up. The stand reminder came on when I was in the middle of grocery shopping, walking constantly.

The move ring will sometimes close when I am at work sitting most of the day, but not close when I have been exercising.

It counted 15 flights of stairs climbed when I did two. It registered 0 when I purposely climbed 5. It has registered 30 minutes of exercise when I did far less, but when I was exercising for 45 minutes it counted ten.

I have done all of the recommended fixes, including updating software, calibration, set my personal settings, checked all of the system settings for wrist detection, location, etc. unpaired and paired. I don’t have any other fitness apps installed. I have tried all of the ones listed on various questions in this forum. I am out of ideas. Help!