Who said you can't be what you want in Sekiro: Shadows Die Twice? This mod may just refuel your desire to replay the entire campaign in a whole new disguise.
Currently, this costume pack includes ten different skins for the Wolf. Some of them are characters from the game, while others are downright bizarre lizard and monkey costumes.
In any case, you can probably find the best one amongst all the skins presented in this mod for your next playthrough.