Pylance is built on their open source Pyright library, which is also available as a VSCode extension. I'm just using Pyright instead and don't seem to be missing out on anything important.
While Pyright the project is still under development, when Pylance was released, it was mentioned that the Pyright VSCode extension wouldn't be developed any more. I'm surprised it still works, but I guess that's more of a coincidence of not breaking API compatibility?