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.
Unless you are using resolvconf and systemd-resolvd, NetworkManager might empty /etc/resolv.conf when you remove the last tunnel. This step is optional, but recommended: