Apparently, systemd-networkd defaults to a route metric of 1024 for all interfaces, while NetworkManager defaults to 600 for wireless and 300 for wired (IIRC) - not sure about wwan/LTE interfaces.

I use systemd-networkd to manage wired interfaces, and NetworkManager to manage wireless interfaces (by setting unmanaged-devices in their config)

When using networkd without any custom RouteMetric= set, this will result in my system preferring wifi over wired, which feels quite unintuitive.

IMHO, networkd should try to use the same metrics here by default.