Not to take anything away from the new pip approach but debugging in vscode works fine with buildout. I use it all the time. just add GitHub - collective/collective.recipe.vscode: Buildout Recipe for Visual Studio Code which has been updated to use pylance and sets python paths in all right places with no extra effort.
Since there seems to be a misconception this isn't possible I posted howto here VSCode debugging with instance and tests using your existing buildout