I don't know if they are or not. I am just a regular person with a home computer. I know how to set up a run a basic localhost server, but I don't really know about the other stuff you're talking about.
If you're thinking of diving deeper into development, I'd recommend you take the time to learn about computer networking. It's not a necessity if your end goal is to stuff HTML/CSS/JS files into a server somewhere, but it'd make your life a lot easier down the line.
https://minecraft.fandom.com/wiki/Tutorials/Setting_up_a_ser...
- https://www.wikihow.com/Portforward-Minecraft
- https://www.technewstoday.com/port-forward-minecraft/
- https://www.youtube.com/watch?v=X75GbRaGzu8
Most of the guide you linked is related to setting up Java and configuring Minecraft itself, you only need the port forwarding bit.
With IPv4 you can do it with a port forward, but the IP listed isn't the same as the IP you'll actually receive the connection on. You can get your external IP relatively easily with `curl ifconfig.co`.
If firewalls or port forwards aren't available to you, pick any of the popular port forwarding methods (here's a list: https://github.com/anderspitman/awesome-tunneling). I'm a big fan of just SSH-ing into an internet connected machine myself (`ssh -R 0.0.0.0:3000:127.0.0.1:3000 server.on.the.inter.net` will expose localhost:3000 on server.on.the.inter.net:3000 and encrypt the traffic between you and the server as an added bonus!) but there are plenty of paid and sketchy alternatives if you don't have a server to SSH into.