You have already asked for permission from them and not gotten it. They are not going to do it the way you want to, so you have to either do more work to convince them, resign yourself to wearing it, or do what you want and deal with the fallout.
After 9/11 I was being followed by racists so I switched from traditional hijab to a turban when out. Changing how you wear it could be a step towards taking it off.
Some here have tried to convince their parents with progressive interpretations regarding hijab. It might be worth a shot.
If you feel you are in danger or will be harmed for taking off hijab I advise you not to do it until you are in a safe place, free from repercussions.
At some point in your life you have to be your own person and not anyone else's. I don't mean you have to be rude about it but if no one in your life is going to accept your autonomy then you have to get to a place where you can be dependent on no one but yourself so you can be you.
And welcome!