Maps app on macOS 15.5 opens to a blank window with no controls

A few days ago while traveling I opened Maps on my MacBook Air to look up restaurants. Much to my surprise all that opened was a small grey window. There are no map controls (zoom, choose view, whatever), just the full screen, minimize, and close circles in the upper left. I cannot resize the window. And there's no maps inside the window. Pulling down the Maps menu there isn't even a setting for Settings.

I chatted for some time with Apple Support. They suggested booting in safe mode (no change) and trying a new user (Maps worked under the other user account). At that point they said I had to reinstall macOS. Since I'm traveling and don't have my Time Machine drive handy I declined and said I'd have to look at that in a few weeks.

In the meantime I wondered if the community had any suggestions. I've attached an image of the Maps window, not that there's much to see. Perhaps someone else has had this and can shed light on a solution.

[Edited by Moderator]

Original Title: Maps in macOS 15.5 Has Gone Completely Blank