What do you mean that it is not working? Did you enable the extension in the Extensions app? Also note that you need to re-log in for an extension to appear after installing it through environment.systemPackages.
I added the lines you proposed to my config, and I can now send files from my iPhone to my computer.
I had to do a log out of my current session to make things work.
But I am unable to send files from my computer to my iPhone. It seems to work, but I don’t know where to find them if it really goes to the iPhone. Can you please help me?
Also, how could I have known about the configuration part you shared?
If there are no usage notes you can probably use environment.systemPackages to install the package.
In this case, you were failed on multiple counts:
The NixOS manual only mentions GSConnect as one of several extensions. And while the installation method is correct, it fails to mention special considerations (ports needing to be open in the firewall when using it over LAN – this is what the kdeconnect module does).
The option search only searches option names, so you would have to know it can be passed to KDEConnect. One benefit of the Options apendix is that you can search it using your web browser’s search – even if it is a bit unwieldy, at least it allows searching descriptions.