The only similarity between chazzanut and opera is that both rely on bel canto singing. But even that is not entirely correct. Opera is a vocal art. Without a pleasent sounding well trained voice, one cannot be an opera singer. . .period. Chazanut is the art of prayer. While the cantor’s voice is one aspect of his stature, it is of far less importance than other factors, like whol he is as a person, his understanding of nussach, his interpretation of the text of the siddur via the nussach. Some of the greatest chazzanim had small or even unpleasant sounding voices (i.e. Ganchoff, Pinchik, Eshel, Belzer etc.) So I’m sorry; having studied both, there is far more that distinguishes opera from chazzanut than invites comparisson.