https://www.wsj.com/articles/SB123353276749137485
https://fee.org/articles/fdrs-folly-how-roosevelt-and-his-ne...
https://www.nas.org/blogs/article/ask_a_scholar_did_the_new_...
(I basically googled "did the new deal extend the great depression" to find these)
Now, you could say that these are all "conservative" sources, and thus invalid. (Of course, you'd then have to throw out support for the New Deal from "progressive" sources, which might also be painful) But either way, it does show that "The New Deal didn't help" is a position held by people.
Whaples, Robert (March 1995). "Where Is There Consensus Among American Economic Historians? The Results of a Survey on Forty Propositions" (PDF). The Journal of Economic History. Cambridge University Press. 55 (1): 142–151. CiteSeerX 10.1.1.482.4975. doi:10.1017/S0022050700040602. JSTOR 2123771.