The thing I can't understand is that netplan is just a bunch of janky C that is almost entirely parsing logic and the thinnest wrapper humanly possible over systemd-networkd/networkmanager that does all the real work. And the abstraction leaks for anything but the simplest cases so your files are targeting a specific backend anyway.
systemd-networkd already gives you simple declarative INI networking files and a dbus interface. I can't find any value-add over just using its backends directly.
I like the chaos of the Fedora networking tools because they let me charge more billable hours as I untangle what the client set up for themselves.
In all seriousness, once you learn Netplan, you get accustomed to 1 config file for all networking needs. I also prefer UFW to iptables. Simple and handles most day-to-day use cases.
systemd-networkd already gives you simple declarative INI networking files and a dbus interface. I can't find any value-add over just using its backends directly.