my apple watch won't open my MacBook pro. latest version updates on both

Update to watchOS 7.1, as it has a fix for unlocking Macs

If that does not work, it should, but if it does not work, then read the following threads

Check out this thread on fixing Apple Watch unlocking Mac

https://discussions.apple.com/thread/251803595?answerId=253458029022#253458029022

Then follow with this thread

https://discussions.apple.com/thread/251826134?answerId=253504359022#253504359022

And

I also found that it took awhile for the iCloud Keychain records to propagate and merge on all the systems. More so when you have multiple devices sharing the keychain (I have 4 Macs, the iPhone, and the Apple Watch). I followed both of the above threads, but it was not reliably working until the next day, when I tried again. And I did have to click the enable check box twice the next day, but then it stuck.

And this thread says they also had to toggle the Apple Watch -> Settings -> Siri -> Listen for "Hey Siri" option off then on

https://discussions.apple.com/thread/251803595?answerId=253782332022#253782332022

Hints (you will understand when you read the first and second threads):

Applications -> Utilities -> Keychain Access

Finder -> Go menu -> ~/Library/Sharing/AutoUnlock

System Preferences -> iCloud -> Keychain