Well "place an index.php file in a folder to deploy" is a lot of server (maybe Apache / PHP) running to support that.

Node typically IS the server. So, you could install express and have a simple web server listening on a port and serving up html or json in about 5 lines of code. Unlike PHP Node is not, in itself, a templating language. So if you want to render HTML pages you'd also need to install something like EJS, but generally node servers are just serving up JSON API, and your frontend would be some frontend framework (React, angular, vue). Although all of that is trending back the other way with NextJS the old is new again and server-side rendering is the hotness again.

Another option is to use a framework like NestJS. With that you do

    # install the nest cli (only needed for starting a new project)
    npm i -g @nestjs/cli

    # scaffolds a new project
    nest new project-name

    cd project-name

    # node server is now running on port 3000
    npm start

For easy deploy. That was kinda Heroku's thing. You just "git push" a node project and it magically knows how to deploy it, but Heroku got bought by Sales Force and murdered from my understanding. There are a lot of alternatives though. AWS, Azure, Google, CloudFlare, Digital Ocean, etc, etc all have similar offerings where you just push a node project to git and it deploys automagically.

Alternatively you can use AWS Lambda / Azure functions (or a dozen other "serverless" solutions) and you can just drop js files (functions) and they run on demand.

For a ProcessWire alternative there are a ton of options. A few I've seen are: Ghost, ButterCMS, Strapi