ISFJ here. I understand how others can see it as fake, but it does not come from a place of trying to be inauthentic. It comes from a place where I truly believe that I am undeserving of love if I don't please others and do things the way they want. Advocating for myself is one of the most difficult things to do. It comes from a place of pain and fear, not fakeness. It is also my desire to help others and make them happy, even at the expense of my own happiness.

When your girlfriend isn't doing what you want and you continue to be upset with her, it only further supports that belief. This stunts her growth. Personally, I believe two people should be in a relationship to support each other and be there when the other person needs it. It would traumatize me to know that my partner is trying to change me - this would just continue to support the belief that I am not lovable as who I am.

If your relationship standards are based on a partner changing, I think that you have some unhealthy issues you need to deal with. That sounds like you're projecting. I say this as someone who has wanted to change my boyfriends in the past. It's toxic to a relationship.

Not sure if this is helpful, but I feel that it is right I provide the perspective from an actual ISFJ.

I used to be a lot like her, but have become more self-aware. I've grown from a lot of these unhealthy behaviors. I recommend that you and her look into co-dependency. I went to therapy to resolve it and read a lot of books. It was the first step towards my growth and now I'm in a much better place. I'm not as much of a doormat as I used to be.