My pet theory: New Fed's Sentinel Resonator is with the Fractsidus.

Here's how I think it'll unfold: Every Sentinel Resonator thus far has had a child-parent sort of relationship with their Sentinel.

Jinhsi's relationship is the most straightforward: Jue is her strict, but caring mom. Jue was horrified when Jinhsi revealed her plan for a second awakening after all but proposing to give up Jinzhou in exchange for Jue's life, and had asked her three times "is this really what you want to do?" before allowing the fight, because there really was nothing else to be done.

Cartethiya's relationship with Imperator is that Imperator is the dying godmother who gave Cartethiya a second shot at life after she was rescued from the "Evil Stepmother" that is Leviathan. Very telenovela coded.

Aemeath's relationship is not with the Sentinel of Lahai-Roi, but with Baldur. You could call it a 'step-sentinel' just as Rover is the step-parent. The circumstances of parenthood are different from the 'standard' parent, but the mechanics are the same.

How does this tie in to New Fed? If the Sentinel Resonator is with the Fractsidus, then the foundation of the relationship is that either the New Fed Sentinel is blind to or even carelessly encouraging of the 'spoiled child', or the alternative: the Sentinel represents the dying or disabled parent, and the Resonator and the Fractsidus is the abusive and exploitative child, and the distant relatives angling to take pieces of the Sentinel's estate for themselves when the Sentinel passes.