(Again: I'm not expert)
You seem to be missing a basic principle of how it works.
HTTP uses port 80.
That is the standard for the internet. Browsers talk on port 80.
Node-Red is a JavaScript platform that may send HTML stuff down to the browser, but it isn't HTML.
It is JavaScript.
@TotallyInformation explained the use of ports.
Anything above 1024 is fine. If you want it below 1024 you need to run Node-Red as ROOT and this is NOT recommended.
I'm way out of my skill set. Read what @TotallyInformation said.
It is just how it is. All Node-Red pages are on port 1880. (Or anything above 1024 if you edit the settings file)
