Dungeons no longer opens nor installs from Windows Store

Originally purchased Windows Store version of Minecraft Dungeons at launch.

Game worked properly for about a year, including updates, Season Pass, etc.

However, within the past several weeks, MD will no longer run from the Start Menu, nor directly from "Play" on the Windows Store. No material changes had been made to our system or installation.

Ran various Windows/Store troubleshooters to no effect.

Even reluctantly uninstalled the game, fearing loss of saved character data, but now "Install" button on Windows Store also does nothing. All commands related to the game seem to pass into the nether.