I'm thinking of practically ghosting a friend because she was a flake with our plans and didn't respond to my text after three days.
Does she not respond often?
She's a flake and she doesn't even apologize
It's understandable to be upset when someone flakes on your plans, but you should tell them that it bothers you. It's better to communicate how you feel than ghosting someone.
They deserve to feel bad.
It sounds like you just want to punish your friend instead of resolving the issue. Maybe you should consider the value of your friendship before ghosting them?