The aspect of economics you point to are also the subject of the book "The Capital Order: How Economists Invented Austerity and Paved the Way to Fascism" by Clara E. Mattei . Her title is a bit misleading. The book mostly focuses on Italy and Britain during and after WW1. Austerity was used in both nations to reinforce the capitalist order-i.e. putting workers on the defensive and ensure financial gains in the economy flowed readily to the investor class.

I don't think that austerity paved the way to fascism. But in Italy it took fascism to impose austerity by edict.

Economists were used to implement austerity by cloaking it in some veneer of nature or science, rather than an explicit political decision