# Get signing keys to verify the new packages, otherwise they will not install
rpi ~$ sudo -Es
rpi ~# apt-key adv --keyserver keyserver.ubuntu.com --recv-keys 04EE7237B7D453EC 648ACFD622F3D138
# Add the Buster backport repository to apt sources.list
rpi ~# echo 'deb http://httpredir.debian.org/debian buster-backports main contrib non-free' >> /etc/apt/sources.list.d/debian-backports.list
rpi ~# apt update
rpi ~# apt install wireguard
https://willhaley.com/blog/raspberry-pi-wifi-ethernet-bridge/