Also, are you actually running the server at the time you are testing? Even if your firewall is actually open on the port, if you are not running the server the firewall on your PC *might* be blocking external access on the port if there is nothing there to connect to. If you have a separate computer on your LAN, you might verify someone in your home can connect to the server to make sure THAT is working properly first.
Running a server out of your home has so many "moving parts." I apologize if I'm asking obvious stuff you are sure you covered. There are details such as your home setup you really don't want to publicize but would be helpful in sorting the problem out. In my case, I decided to pay for cheap hosting rather than have to deal with all this.
That would depend upon your PC firewall settings, which *may* block ports where no server is running. Or your firewall might block anything it isn't aware ought to be open to prevent trojan programs. A good security system is like an onion, in a sense. There are different layers so no one thing will completely open your system. That makes this stuff seriously complicated in a hurry. Being "easy" means "easy for someone to break into my computer system."
You should first get the server running on the port. It sounds like this is on your desktop computer. Then you should be able to connect to the server from the same machine. Then test it from some OTHER server on the same LAN. In my case, I could have my wife connect to my MC server from her computer. If you can't do either of those, nobody from the outside is going to get in.
After you test that, then you can have a trusted friend attempt to connect to your MC server from the outside. But testing "layer by layer" is really the only way you can be sure your security is set up to permit the connection. That's pretty much why most people skip that noise and use a service provider or Realms, or in the case of Minecraft Bedrock they do magic to make it "just work", usually. Except when it doesn't.