Q1. Is there a map of where Ballard searched in 2019 (on the TIGHAR website, or elsewhere)?
Q2. If not, did his expedition search southwest of the shipwreck site, or only northwest?
A1. It may be that the brown area in the slide at 56:12-56:25 of the online video,
https://www.youtube.com/watch?v=f21s7sKB3qM, from the October 2021 Arden presentation in Delaware by Ric Gillespie, may show the Ballard search area.
A2. If so, the answer to Q2, ignoring the "if not," is yes, with some deeper water leftover.
This video, by the way, is very good despite some technical difficulties moving from slide to slide and the coughing. Besides how it pieces together everything, and informs me on the sleuthing logic better than I was informed before, it got me past some minimal doubts I had about specific details of the TIGHAR thesis. These had to do in part with (a), at 31:22, the segment where Ric Gillespie explains that Betty, interviewed in person, told him that NY NY was the way she wrote New York CITY. Some skeptic I read had challenged that NY NY referred to New York City as opposed to just New York, and thus had challenged the "Norwich City" similarity idea. Also, (b) later parts of the video got me more informed that the idea of where the plane landed was strongly based on subsequent islander reports of where plane wreckage was (thus eliminating my doubts as to whether the plane might have ditched in the lagoon closer to the 7 site, if there was a lagoon way for it to disappear before the July aerial search). So between (a) and (b), I've over any lagoon landing discomfort or possibility, ruling it out, whereas before, I wasn't really sure why it had been so ruled out by TIGHAR when there had been little exploratory scuba (or other) diving there.
My other thought from the video, however, is that the shipwreck might (emphasis might) have had more opportunity to be torn apart, situated where it was on the reef edge with waves and storms hitting it, than the plane would have opportunity to be torn apart, if it had slid off towards and into the deep within a week of the landing. Ballard's Titanic, for instance, sunk in 1912 a quarter century before 1937, still has a lot intact as opposed to everything having crumbled to pieces. So a related curiosity I have is:
Q3. If we suppose that a portion of the plane, wherever in deeper water, were still intact rather than crumbled into scattered tiny pieces, what portion of the plane would be likeliest to be most intact and largest?