Yeah, well, I never got any real help from T-Mobile, no estimate of when the problem could be resolved, nor any options for a phone replacement.
In another post, I did post what I did to resolve the issue, which was exactly what I did NOT want to do: a full factory reset, and then never applying the update again. I lost a bunch of data and history, it took a couple of days of time to get things back to where they were, and, for all of that, I still don't have the single feature that I wanted, which is the ability to move apps to the SD card (like an old Galaxy S2 has been able to do for years).