Lock/Unlock with Wear OS & Android Phone
I made an app/program to do exactly this.
It is called Umwelt, you can find on my website (gadgetish.com). It does both lock and unlock, allows to adjust the distance (as you requested), notifies your phone if anyone tries to steal your laptop, allows to lock/unlock with your phone fingerprint reader and blocks the screen saver when you are within Bluetooth range.
You'll need to install the program in your Windows PC, an app in your Android phone/smartwach and select a Credential Provider in the lock screen.
There is also a version for Mac, but it doesn't have all the Windows functionality. However it works with any BtLE device.