Oooof. Okay for starters, know that your kid is just a kid at the end of the day. They will find their own hobbies and habits as time progresses. This might not be so much of raising your child as gender neutral, rather raising a child without enforcing gender stereotypes, which I happen to agree with. Grooming a child because of whats under their diaper toward certain hobbies, toys, or activities, is weird to me. but this is just a me-view.

(personally, when I was very young, I was groomed away from 'boy-oriented' toys. told girls werent allowed to play in the dirt and would be pushed away from playing with blocks or rough-housing and made to play house. the look on everyone's faces when I insisted on two moms while playing house as a 4 year old is something I will always remember. I am now a bisexual adult woman who works in construction, fixes bikes & cars on the side, and teach kickboxing classes. I am also hilariously girly and femme, like prom queen degrees of girly. If I had been allowed to like what I liked when I was a kid, I would be infinitely more successful & wouldn't have felt as pressured to go to college for a liberal arts degree to one day have a job in a more delicate field. I would have gone to school for construction or a trade school for carpentry, but instead I only got to truly explore what I was passionate about after I was out of the grasp of the family and community I grew up with. That's harmful gender stereotyping & I think that's what your wife is trying to avoid)

I think a good compromise to her proposal would be to highlight how much you both love your child immensely & that imposing anything on a kid in terms of gender and sexuality is weird. The sexualization of children is super super not okay. Thinking "oh you're a toddler, but because you have a vagina, even though you don't know what that is yet, you cant play with certain toys or do certain things" is weird.

Let her know how much you love your child. Ask exactly what she means by gender neutral and what that would mean in your day to day. Does that mean using your child's name more, i.e. referring to them by their name (Marissa has playdate this afternoon versus 'she has a playdate this afternoon'? Does that mean letting your kid cut their hair the way they want? Does it mean using they/them (which, its not horribly difficult)? Does this mean buying different clothes? Figure out the scope of what she means.

Dont panic. Try to understand what your wife means. You may find there is a lot of rationale to this. If not, then the ball is in your court

Know that this is coming from a place of you both loving your child and wanting "what's best". No malice is intended.