how to activate walking assymetry on apple watch 6?

I believe that is more a function of the iPhone. You are supposed to wear the phone near your waist. Check out the health app on the iPhone, Mobility, Walking Asymmetry, and About Walking Asymmetry.

Hi Tulpia,

Welcome to the Apple Support Communities!

We understand that you'd like to activate asymmetry, respiratory frequency and vitality on your Apple Watch, correct?

We've included a couple articles below to ensure that your data is being recorded accurately while using your Apple Watch:

Get the most accurate measurements using your Apple Watch

Calibrating your Apple Watch for improved Workout and Activity accuracy

We hope this helps.

Cheers!