It may have shortened the duration but I think there were way too many other structural problems to have avoided the depression entirely. It's not clear farmers could have paid their mortgages even at lower rates due to rapid deflation in commodities caused by the tariffs and overproduction from industrialization.

Don't forget, the secretary of the Treasury at the beginning of the depression, Andrew Mellon, was a staunch believer in liquidationism. Effectively, liquidate everything and everyone to get the rot out of the system. They actually welcomed deflation and claimed it had solved the '20-21 depression.

New York banks were going to fail no matter what. Over leverage in the stock market and literally lending Germany money to pay reparations to GB and France so they could repay war debt to the same banks. The stock market was in a bubble due to industrialization and mispricing currencies post war and was bound to crash, taking all those over-leveraged banks with them.

The Fed added fuel to the fire by raising rates in a deflationary environment, but that environment already existed due to terrible government and near zero banking regulations.