Thanks for all the theorizing and the potential solutions. Turned out the problem was most likely a corrupted configuration and a too small SD card. I am not sure if that is what actually drove the failure, but all is in balance now.
Interesting observation: I could not get the latest image (5/28) all the way through configuration so used the March image and updated/upgraded my way to present day. The May image would repeatedly forget settings and give me a ration of crap - particularly by resetting the hat to naught and stripping out the country settings. (Come on y'all I know we are "toxic" but don't take it out on us ).
I normally don't have the patience to wait for a Pi Zero to figure out what it is supposed to be doing, so in the past I have used a Pi3/4 to configure, then moved the hat and SD to a Pi zero to run... Out of an abundance of caution and to my frustration I walked through the entire config on a Pi Zero.
Since I acquired a new hat of the same variety, I put it on another known good Pi Zero and configured it from the ground up with a new 32GB SD. Once that was working I swapped hats and the old hat "found its3lf" so I backed up the config to disk. Next put in a new March image on a fresh SD card, booted, restored the image config from disk and then tweaked the configuration to individualize that one... now both hotspots work nominally. I'll burn them in for a day or two then decide whether to keep both or find a new home for one. I have too many anyway.
MMDVM_HS Hat hardware