Issue is resolved, although not from the user interface that you screenshot in this reply. I never arrived at any interface that looked like that.
You're correct on the extra fee to store docs. From a different page, I was able to get to my 2018 return, which turbotax only allowed me to download after I had proceeded through filing my current year's taxes in sufficient depth. The notification said that I merely had to "select a product" from the filing page before being able to download my return from last year. That in itself is BS enough, but even at that, I wasn't able to actually download until I had proceeded several steps further into filing for this year with TurboTax (which I am not doing, and thanks to this experience, never will again).
