While there is some general compatibility work required in the background, a removal of the hard barrier between male/female routes and allowing players to choose their own pronouns would be the main factors in broadening the gender spectrum. When it comes to non-binary gender options in games, it's not as hard to implement as it may initially seem. Gender-locked features or outfits are typically an inconvenience at best, and exclusive at worst. It's an easy way to allow a broader spectrum of gender expression in-game. The trailer for Splatoon 3 implies that the player character doesn't have a male/female gender setting, and the player characters in Animal Crossing: New Horizons have some gendered 'styles' but aren't necessarily gendered in-game.
More games are starting to embrace genderless character creation.
