For integers \(m,m' \geqslant 1\) , let \(\pi \) and \(\pi '\) be cuspidal automorphic representations of \(\textrm{GL}(m)\) and \(\textrm{GL}(m')\) , respectively. We present a new proof of zero-free regions for \(L(s, \pi )\) and for \(L(s, \pi \hspace{1.111pt}{\times }\hspace{1.111pt}\pi ')\) under the assumption that \(\pi , \pi '\) or \(L(s,\pi \hspace{1.111pt}{\times }\hspace{1.111pt}\pi ')\) is self-dual. Our approach builds on ideas of “pretentious” multiplicative functions due to Granville and Soundararajan (as presented by Koukoulopoulos) and the notion of a positive semi-definite family of automorphic L-functions due to Lichtman and Pascadi.