macOS 15.2: "No route to host" for local LAN devices beyond router

Updated yesterday from 14.7.2 to 15.2. Today, on first post-update attempt to access a device on the local LAN beyond the router, either by ssh or ping, get "No route to host." Can access the internet and the web interface of the router at 192.168.50.1, but not beyond it to any device at 192.168.50.xxx. These devices can access the internet and each other.

Having found earlier today that I had no ethernet connectivity, I was able to determine that I had to add ethernet service in System Settings > Network. So I'm thinking there might be some other macOS 15 setting difference from previous OS versions that is causing the subject problem.