I know gal is considered an equivalent, but the only people I’ve ever known to use it were Girl Scout leaders and square dance callers, so it doesn’t feel at all equivalent to me. I don’t know if this is widespread and/or why the word never gained as much traction as “guy,” but I definitely don’t enjoy being called a gal. It feels infantilizing and othering to me, like when people say “and dudettes!”
Interestingly, gal comes from “girl,” whereas guy comes from guy fawkes. I would have made a very unwise bet that “guy” was older.