I just found out that in VSCode you can define a remote Jupyter server and edit the Jupyter notebook from within VSCode. You only need to define the URI of the Jupyter server. I was checking on the Google Colab but didn't find an option to get this URI.
Is there an easy way to link both the VSCode and Google Colab?
No, this isn't supported for a variety of reasons, e.g., Colab requires authenticating with a Google account, which isn't supported by vanilla Jupyter.