Tbf the union busting and wage flattening was Reagan. That stuff wasn't under Volcker purview. Volcker was nominated by Carter, the inflation was already there and was something the admin was voted in to do something about.
The inflation was there regardless, the interest rate is supposed to rein it in. A high interest rate does cause austerity but high inflation is unsustainable in other ways and can very easily become hyperinflation.