i have a doubt concerning destiny in islam and that "everything is already written". So qadr basically means that we're on this dunya and it's already certain that we're either going to Jannah or Jahannam, so we're on this earth to just collect proof why for ourselves why we're going there on the day of judgement.
Now my question is, how come some people are basically born to suffer/enjoy (in hellfire or paradise)? If Allah already decided our guidance, it just means that he wanted us in that place anyways. Why is it that some people are born to not be guided and do bad, just to end up in Jahannam being burned? The same goes for people who are guided and who will enjoy their afterlives forever without a punishment? In that sense it's not their fault but just the will of Allah.
I hope y'all understand what i mean because my English obviously isn't great. I don't want to have doubts about islam but this one makes me insecure.