There might be a misunderstanding - either on how I read your request or on how you use the feature. 🙂
To generate a new version of an existing API call, you use the New version
action an then you get the identicall call (same name, same configuration), just with a higher version number. You can then make changes to this new API version. There is no need to copy things and change version numbers or names afterwards. You can have dozens of the same API running at the same time, to make sure that pre-existing scripts/services can continue to use older versions without disruption.
If you want to create a different API you would normally just create a new one. Usually at least, different APIs use different configurations and so copying them is not often useful. But even in this case, you can generate a new version of an existing API and then rename it to get a copy of it. Then you have 2 differently named APIs that you can update and version separately.
I think, these are the use cases you named, but I might be wrong.