She just let that medicine poisoning guy become her allies even though he was also trying to figure out how to kill her. I mean I get it that the medicine guy is useful but what if decided to poison her whole castle and frame her.
Then there was her lover who kept using her as bait to his plan even though some of it would've killed her if she wasn't immortal like when he made act like she was killed by the empress by poisoning her and slitting her throat and the goal was to frame the empress's eunuchs. The cost was big because of the pain of being slit but the bargain was small. What can a couple eunuch can really do to the empress. As long as her own child is alive she is still a threat.
I think the most annoying to me is when she healed the empress baby in womb with another man while knowing that she was about to kill her. Like what's of the empress's child when you already won her brother over that there's no way you'd harm her.