If they gonna use her like this, how about give HER the agency to decide for herself? The kingdom is lucky she still lives there after how they treated her initially and the King is the worst offender letting his pathetic don run rampant. But no, he conveniently pushed all the blame on a bunch of teenagers.
Say "I'm gonna protect her when things go wrong" is the same as "she'll face danger, there's a chance that she'll get seriously hurt and the backlash of any mistake would ruin her mental health since we're using her as scapegoat.... but hey, that's a sacrifice I'm willing to make, watch how guilty I look rn". That's actually gross to read, you can see how the former Crown Prince got his personality.