Instructions to have Wireguard NetworkManager plugin

sudo apt install libtool libglib2.0-dev pkg-config autoconf automake intltool build-essential libgtk-3-dev libnma-dev libsecret-1-dev libnm-util-dev libnm-glib-dev libnm-glib-vpn-dev libnm-gtk-dev resolvconf wireguard wireguard-tools

wget https://github.com/max-moser/network-manager-wireguard/archive/master.zip
unzip master.zip

cd network-manager-wireguard-master/
./configure --prefix=/usr --sysconfdir=/etc --libdir=/usr/lib/x86_64-linux-gnu --libexecdir=/usr/lib/NetworkManager --localstatedir=/var
sudo make install
cd ..
rm master.zip

# if you delete the folder you will not be able to run 'make uninstall'
rm -Rf network-manager-wireguard-master/

Now go setup your VPN using NetworkManager.
The VPN name must be wg#
In the IPV4 and IPV6 tabs you must set the disabled radio button.