Preserving facial blend shapes?

Hey everyone,

I am very new to this and I have been playing around with a 3D model, specifically this one: https://assetstore.unity.com/packages/3d/characters/humanoids/1-toon-teen-135513

It includes a couple of animations and blend shapes for facial expressions.
I've imported the model in mixamo to get new animations and exporting them to Unity, but when using them the facial expressions has not been carried over and the face is just 'stock'.

Anyone have an idea on how I can get the facial expressions to be preserved with the mixamo animations?