VS Code - Code Helper process using more than 100% CPU on macOS
The behaviour you describe could either be a bug in VS Code or it is intended behaviour simply because the numbers of files you have require large amounts of CPU time to process. I strongly suspect that the problem is a bug.

The issue you have found have the same externally observables as your problem, i.e. the CPU usage of Code Helper is very high. However there could be many different reasons for that to happen. Therefore it is not a problem that that specific issue has been closed for outside comments.

I would highly suggest opening a new issue instead. Go to this page:

https://github.com/Microsoft/vscode/issues

And click the "New issue" button.  Select that you want to file a "Bug report". Then please describe everything carefully, including which of the recommendations you have tried that did not work.

Hopefully the VSCode team will be able to fix the bug and release a new and fixed version.