We investigate the neutrinoless double beta decay ($0\nu\beta\beta$) process, focusing and commenting on the results reported in \cite{Lisi:2023amm}, in the case where both light and heavy
Majorana neutrinos contribute independently without interference, . Our analysis incorporates recent computations of
nuclear matrix elements (NME) from different nuclear models. We put bounds on the contributions of light and heavy
neutrinos to $0\nu\beta\beta$ decay with current data, and we study the impact of potential signals at $>3\sigma$ for
forthcoming
projects such as nEXO, LEGEND, and CUPID.