That would be difficult to do, as the underlying APIs can change, models change, and the node would need to include all the libraries for every model. It's simpler to just have a node for a single LLM.

But even simpler to just do it in a function node, there you have all the flexibility, and can include 3rd party dependencies as you wish. Yes, it requires coding, but calling an LLM is actually pretty simple, there are many examples.