I did not find it this in a guide, so I guess other opal users might save a click and find an answer here:
It's possible to use a more recent version of node.js by installing nvm from https://github.com/nvm-sh/nvm (you will need an ssh user).
Currently opal ships with node.js v.10.22.1. Unless you need to serve a node application, you do not need to create a node application from the control panel. You can use node anywhere. For Jamstack sites (11ty, gatsby, ...) a nginx static html5 application will do.