The Oath feels like such a Nothing Burger action.Instead, you could have tried to reassure him that you would do everything in your power to protect her. Made it an oath even. But what would your words mean to him? You weren't a knight after all. Not yet at least
Compared to possibly gaining an ally in both Gwayne and Otto, this is just shuffling off Gwayne back to irrelevancy. Supporting both of his children will go a long way to tilting Otto towards being pro-Rhaenyra after the long string of back and forth we've had with him.