Is type-inference a guarantee that untyped code will compile, or is it a best effort to reduce the work needed?

If you are already familiar with dev containers (docker based), you can have a one click step by using the haskell dev container in vscode: https://github.com/microsoft/vscode-dev-containers/tree/main/containers/haskell

It comes with stack and should be compatible with this tutorial

I'm not sure yarn has a built-in node version switcher. nvs might be another tool to mention here.

https://github.com/jasongin/nvs