The suspension of disbelief has nothing to do with historical accuracy. It is up to the content being presented and personal context. I assume you suspend your disbelief in other games - like sci-fi, FPS, etc. and many of those are no where close to being "realistic".
With that, if you (general "you") can't suspend your disbelief because it is a woman leader, maybe that has something more to do with your personal beliefs than it is about the game. Chances are it is 50/50.
All I know is that life is full of ****, and after a long day of work or whatnot, people want to escape into their favorite things.
There are "male" movies and always have been, just like there are female manga genres in Japan, Korean dramas for women, boy bands for women, etc. I like Kyle MacLachlan. In Sex in the City he's just an NPC with a penis, not a multidimensional human being. That's cool, because women deserve their stories too where they're the center of everything. This is so common in storytelling and very effective.
In Bannerlord, adding more women and equalizing their skills to men does make it cool in many places. I like bumping into female lords on the battlefield, or rolling a woman just to marry the hunk with the best bow skills. It's not the same as 2016 Ghostbusters, or weird **** like casting a black woman as Gandalf in Lord of the Rings. It often goes too far, but in this game it seems fine.