Espressif's product line is so big that I can't keep track of what is what, and their web copy seems to be written by someone who heard about their products through a friend. I'm working on a design that one of their modules might be useful for, but I don't want to dig through dozens of product pages, to try and find the specs and capabilities. All I need is a single simple comparison chart.

I've tried searching for comparison charts other developers might have put together, but there's nothing up-to-date and complete.

I agree! Unfortunately the best information appears to be in the individual series datasheets, however I did find this page to be helpful: https://products.espressif.com/#/product-selector