I did my usual FULL profile backup, uninstalled the nightly from yesterday, installed the new one that just appeared - and crashed immediately to the crash reporter, BEFORE even seeing the prompt for the "master password".

Scrounged and installed one of the early "2.53.17b1pre" builds from about a month ago, seems happy with my profile.
This is really unusual... note that I am on Windows 11 "BETA Insiders/preview track", so they aren't exactly bleeding-edge - OTOH, they *did* just update to "Windows 11 Pro 22624.1470" yesterday.
Anything else anyone wants to know?