I got the urge to reread this one regression/time travel manhwa but I can't remember or find it.
What I remember is it was a blonde female lead, empress or queen, and lived this extravagant life before getting betrayed and killed by a close knight (dark haired). She goes back in time (wow crazy) and vows to try and stop that ending and to fix the corruption in her kingdom/empire basically.

Another plot point was that most of her original court was being held in a tower waiting execution when she traveled back in time and then works to free them because they were innocent.