is applewatch handy is you are lefthanded

You can change the watch face orientation

hhttps://support.apple.com/guide/watch/change-language-orientation-apple-watch-apd0bf18f46b/watchos

The above has lots of pictures showing the watch in different orientations with the Digital Crown in different positions.

Here is Apple's webpage on orientation

https://support.apple.com/guide/watch/change-language-orientation-apple-watch-apd0bf18f46b/watchos

Whether you are right or left handed is not an issue. The  Watch can be worn on the right or left wrist.