Putting this here to remind myself the next time I need to do this ;).

Update package information

sudo apt update

Install WireGuard

sudo apt install wireguard

Reboot

sudo reboot

Debian 11 uses resolvectl, symlink it to resolvconf so WireGuard can use it

sudo ln -s /usr/bin/resolvectl /usr/local/bin/resolvconf

Enable resolved

sudo systemctl enable systemd-resolved.service

Start WireGuard

sudo wg-quick up PATH_TO_YOUR_WIREGUARD_CONF

For reference: https://superuser.com/questions/1500691/usr-bin-wg-quick-line-31-resolvconf-command-not-found-wireguard-debian

https://superuser.com/questions/1427311/activation-via-systemd-failed-for-unit-dbus-org-freedesktop-resolve1-service