I think if you want that, JavaScript isn’t the right tool. The single threaded simplicity is a big part of why it is a useful tool. You can always spin up external processes from within your app, or use a load balancer or queue to share work with multiple identical processes.

The idea of just horizontally scaling up a node process wouldn’t make a lot of sense. How would you share scope between the different processes for example? You would need a whole new construct, at which point you’re really throwing away the advantages you had and you should probably be using a different language.