How to open my unity script custom package in vs studio as a project

I followed the steps in the documentation on how to create a custom package and it worked, I'm currently using the local way with the folder outside my main project structure, but referenced as a package.

The problem is: Since the package was not created as a .net project it doesn't open in vs code as one. This means that there's no intellisense and other features. I'm able to write a code like this, for example:

However the GameObject keyworkd is not being highlighted since it was openend as a file.

How can I setup this environment? I've looked into other open source packages, but none of them seem to have a .csproj file for them.

 

This might be relevant?

https://forum.unity.com/threads/how-to-get-intellisense-setup-for-a-custom-embedded-package.859015/