Hi Prejie. The problem is that uniforms, unlike other clothing options, have different internal IDs according to your character's gender. Using clothing cheats in recent PkHex should add the missing uniforms for the updated gender, but wouldn't remove the wrong ones, so, according to the swap you made, you should edit the block named KFashionUnlockedClothing and remove the values for the wrong gender and add the correct ones.
The following are female ids:
Base uniforms: 581B, 591B, 5A1B, 5B1B
Preorder uniforms: 601B, 611B, 621B, 631B
Kitakami kimonos: 691B, 6B1B, 6D1B, 6F1B
Unreleased tracksuit: 711B
These are for males:
Base uniforms: 5C1B, 5D1B, 5E1B, 5F1B
Preorder uniforms: 641B, 651B, 661B, 671B
Kitakami kimonos: 681B, 6A1B, 6C1B, 6E1B
Unreleased tracksuit: 701B
Keep in mind that, while this fix seems to be working (for what I observed), it's always dangerous in recent games to edit sensitive things like player gender, because there could still be a number of undocumented flags in the save structure depending on fundamental and manipulated data.
Good luck!