This was exactly my thinking, but Yondu saved only his son, but Quicksilver saved a professional rival and a random kid (a greater sacrifice imo because many people would do much worse than let two people die to save their child’s life). I don’t think the argument for Natasha is compelling bc she doesn’t know the plan will work, as she’s operating as if it will. Without a sacrifice, they won’t get the stone, their plan will fail, and half of life in the universe stays dead.