Received today. So…mystery solved? The item is not actually in stock, evidently. The bizarre “2 days after ship” was evidently the right (only) choice, and I “chose poorly,” despite the Amazon glitch(?) showing it in stock.
TLDR: I was in Amazon’s Upside Down and didn’t know it. Looks like @GGX called it.
But why in the world did it take 3+ days to figure it out, on Amazon’s end?