I’m not down for an overly growly Batman voice, if the actor does not naturally have a voice that low.
I would also argue that the Batman voice is essential.
A certain jawline does seem to be required, since the cowl covers everything but your mouth and chin.
Looking back at past Batmans from Adam West and Michael Keaton to Val Kilmer, George Clooney, Christian Bale, and Ben Affleck — they do seem to have good chins.