You might wish to try using these settings:
- On your iPhone, in the Watch app, go to: My Watch (ta
> General> Wrist Detection - turn this on.
- On your iPhone, in the Watch app, go to: My Watch> Passcode> Turn Passcode on (choose either a Simple Passcode or a more complex one).
- Also on the Passcode settings screen, enable Unlock with iPhone.
After putting it on your wrist, your watch will then unlock after whatever you do first: either unlocking your watch manually (by entering the passcode) or unlocking your iPhone.
It will then remain unlocked (including when the screen is asleep) until you remove it from your wrist. When you remove your watch, it will lock automatically.