I recently switched from Ubuntu to FreeBSD, and systemd-networkd is what I miss the most. Network settings in /etc/rc.conf totally feel like a bandaid on a bandaid on a bandaid.
What you need is dhcpcd. I use dhcpcd on Linux as well, rather than systemd-networkd. It's better and doesn't come with any hardcode Google or Cloudflare DNS servers as systemd-networkd does.