WireGUIde is a free and open source graphical user interface for WireGuard: https://www.wireguard.com/. Using WireGUIde you will be able to easily manage you Wireguard client connections on GNU/Linux without the need to use the terminal. WireGUIde uses NetworkManager as a backend, so it is compatible with connections set up with nmcli.
WireGUIde requires a fairly recent version of network-manager, and of course wireguard support. For example, while wireguard is available from buster-backports, network-manager for Debian Buster is too old (1.14.6). WireGUIde is known to work on Debian, Ubuntu and Fedora versions with network-manager >= 1.22.10. That means that it will work on Debian Bullseye, Ubuntu Focal, Ubuntu Groovy and Fedora 33 or later.
It is no longer recommended to install using pip or the previous created appimage, since this project uses dependencies that are not easily packaged using universal binaries or python packaging (infact appimages and pip project has been removed). Instead the native debian/rpm package is recommended.