@OakdaleFTL Thanks for the advice. I've tried both, bool and boolean, and they both work. And yes, issue the command without Vivaldi running.
I'm stumped. I've deleted 192.168.44.54 from Keychain, and (like I said above) wiped out Vivaldi for a fresh start, and upgraded to MacOS Sonoma. Something is buried deep in the bowels of the system.
Joe