Please add a flag to generate Wireguard configs which work with systemd-networkd. Especially the DNS settings are tricky. To get it to work I always have to replace the DNS config with:

PostUp = resolvectl dns %i <dns server ip>; resolvectl domain %i "~."; ip route add <server ip> via <iface ip>; sysctl -w net.ipv6.conf.all.disableipv6=1
PreDown = resolvectl revert %i; ip route del <server ip>; sysctl -w net.ipv6.conf.all.disableipv6=0

I believe this is a quick fix and it would make using wireguard configs easier.