This is the design I came up with for the other main character of my personal project. I started with Hilda and based Yngvilds design on those previous choices. Which is also why you can find the concept sketches in the Hilda-post (here: https://www.artstation.com/artwork/OogD6w).
Yngvild is higher rank than Hilda, she's the commander and I chose presenting her in her formal outfit because I think it supports her personality well and shows that hierarchy better. For this too I used Autodesk Sketchbook Pro except for the final design which I used Photoshop for.