Thanks all, for the support and info. I need to work back through some of this stuff to understand what happened and why.
There’s a bigger backstory I will post in another thread on a different subforum. The “no crank” (that’s truly what it was - nothing) symptom late Friday evening came in the last hour of preparation to take the truck on a planned long drive event.
I awoke in the wee hours of the morning on Saturday, with a spare starter in hand ready to swap the switch and/or the whole thing as a Hail Mary attempt to make the trip happen. After some fiddling with the battery cable connections, JW fired right off. I don’t understand - I had done plenty of fiddling with the battery connections the evening prior.
Anywoo - truck ran pretty flawlessly yesterday over 380ish miles to the event and back. One little hiccup that may or may not be related to all this. I’ll type details on that later.