Sometimes life is strange. You also have the grandchildren of the King of Sweden who are children of HRH Prince Carl Philip and HRH Princess Madeleine - their children are also Princes and Princesses without a prefix. The same goes for the sisters of the King of Sweden except HRH Princess Birgitta. Same for the sisters of the King of Norway. Prince Harry, The Duke of Sussex and Prince Andrew, The Duke of York are also technically still HRHs but cannot use it. I am sure there are more examples out there. So you see you can be a Prince or Princess without a prefix
