Siri Never Works from MBP - Always "I'm Having Trouble with the Connection"

Hi, I have a MBP from November 2023, M3 Chip, 128GB RAM, running Sonoma 14.5. Siri has never worked on this machine. I have it enabled, and I can connect to the internet without issues.

Siri works without issue on the same network connections on the iPhone and Apple Watch. If I have all of them next to me, Siri defaults to my iPhone (reasonably expected). However, if my iPhone isn't nearby, and I am working on the MBP, Siri will never work -- 'she' always tells me there's a problem with the connection. It does the quick "ding ding ding" noise like I don't have an internet connection (I do), shows what looks like fragments spinning, and then tells me there's the connection issue.

I don't *need* Siri on the MBP, but it seems strange to me that it doesn't work - and has never.