What does this do? Opens the 1714 and 1764 ports normally blocked by the Gnome Uncomplicated Firewall (ufw). These are necessary to connect to the KDE Connect app.
Refresh listings on phone and pc and it will connect just fine
If you have UFW enabled, the UFW (Uncomplicated FireWall) may not be allowing access. I do not believe the GNome Desktop blocks those ports, nor that it would have any incentive to do so.
If UFW is enabled, you can allow access with the command posted by @Wozak
You could always look up what service the port numbers are assigned.
A quick search has provided the following page: Service Name and Transport Protocol Port Number Registry. Which is the port numbers starting around 1699. This clearly shows that the proprietary kde connect service, sesi-im, is assigned to that port. This makes sense.
If you flip to page 31, you will find 1746, which is the ftrapid service. You can Google this as well, but common sense the service is file transfer rapid. Again, an expected service on an application that connects to and communicates with your smart phone.
Paranoia is all fine and good, but at some point you need to investigate what your computer needs to function. Ignorance feeds paranoia and fear. Understanding will allow a calmer, informed use of your computer.
It is safe to open these two ports since kde connect has never and does not now allow or include advertisements, are not reported as spam or maleware and are used by millions of people.
If you aren't sure, search. It is the best way to get understanding. Most of us are volunteers with no computer training. A few of us have computer training. What people don't realize is that we search, and have found keywords that allow for us to find solutions for just about any problem.
In your searches, use "Ubuntu 20" as this is what Zorin is based on.
Keywords are ideal, instead of full sentences. How you word it will be the defining factor. What you have questions about are what will drive you, but be open to adding questions and changing the questions to find answers.
Being new to Linux doesn't mean your experience with computers is irrelevant, it's only applied differently.
This makes a lot of sense and I do not believe you have asked any "stupid questions".
I am, at times, too rushed going from one thread to the next and am too brief in my posts (While other times, I am too wordy).
I use KDEConnect on Zorin OS Lite with 1714:1716 ports permitted and have for years, now.
That isn't what I meant. I was sharing to enlighten you as to what had helped us help others.
Please don't take it that I'm talking down to you or admonishing you for your question. It is a valid one.
This is a learning experience beyond what you asked. It will help you in the future.
Not all problems are resolvible by searching. Sometimes it takes creative solutions with further understanding than you have... and that's fine. That doesn't mean all questions and issues are beyond your ability.