For that matter, everybody here is using the internet. My six year old grandson doesn't know what a real phone is
If you took all your technology away from her, which is absurd in my opinion, then she'd just go elsewhere to use it. Sort of like kids who are banned from certain movies go to the homes of others to watch them. I think her main issues have nothing to do with the game. A lot of kids like to play games and you can only control it until they are out of the house.There is nothing wrong with gaming as an adult.
My oldest son is 37 and has always been into gaming. Yet he does work, have a house, have a good job, care for his child, pay child support on time, and does what he needs to do. He is my difficult child yet he is very productive and his GFGness has nothing to do with gaming and, at his age, I have no control over it anyway. I didn't cause it nor did you. It just is.
I'm glad you are getting help for your daughter as it does seem as if something is wrong. And you are right, of course, that most teens are not unduly rude to their family. Reclusive, sometimes. More interested in their peers, of course...that's growing up. However, most of us come here because we are aware that our children/adult children exceed the "norms" of societal behaviors and we are looking for help and to learn how to cope with it.
Like everything else in life, read everything you see and take what you feel is helpful and leave the rest. I have learned a lot from this forum in the posts of certain people. Others, while they may be totally valid in their thinking, don't resonate with me as well. I tend to just take what I need and feel is good and leave the rest. Like I said, we are not professionals and we are all struggling or we would not be here.