Is it haram not having your dads last name

I’m a 16 year old girl (turned 16 about a month and a couple of days ago) and about a couple of years ago (1-3) I heard that not having your dads last name was a sin/wrong and that there was a punishment for it/not being able to enter jannah. For reference I was raised by my mother and my father is not in my life. But he was given a choice when I was born to write his name/last name down by my name but he expressed that he did not want me to have his name. So my mother wrote my uncle’s last name (they are full siblings but my uncle has a different name then his real one his documents) so that if something happened to her I would go to him. Now the country I live in needs the father’s signature if I want to change my last name to his name (I do believe that only when you’re a minor ) but I do not have contact with him, and have not seen him since my 4th birthday (I can count on 1 hand how many times I have met him (5) ) but when you turn 18 you have the freedom to change your name to whatever you want (though it takes a couple of months). Now we come to what I wanted to ask is it permissible to change my last name to my maternal grandfather’s name and last name (his name is Hassan mohamud). Ps I want reply’s with proof of it being permissible/haram and I would appreciate it if a sheikh or Islamic teacher could answer this since I want an educated opinion.