GSConnect is a complete KDE Connect protocol implementation written in GJS for Gnome Shell (requires Gnome Shell 3.24 or newer). That means it doesn't need KDE Connect or any KDE dependencies on your Gnome desktop. The KDE Connect Android app is still required.
To be able to use GSConnect, your Android device and computer need to be in the same network. If you're using a mobile phone connected to WiFi and a desktop without WiFi, make sure network isolation is disabled in your router.