Something I think that makes Rose's trying to get Atalanta back from Khorne more of a catch 22 situation is that no matter what he does he can't win. Because if he fails to do so then he's constantly chasing the ghost of the woman he loved that is a Daemon Princess to Khorne and by proxy. A living reminder that he failed the woman he loved with all his heart and chose to become an outlaw for.
But if he does somehow free her from Khorne's grip and gets her back In his life. Now he has to deal with Khorne coming for his neck personally since an entire Chaos God is gonna be PISSED that one of his Champions got poached by someone. And as such Bloodthirsters, Bloodletters, World Eaters and Khornate Chaos Marines will be on him and Atalanta's ass more than ever. In addition, to the fact that with the Lioness and Guilliman in play and a entire Imperium of Man who has been the victim of a Daemon Princess of Khorne's rampages for millenia and have lost countless loved ones to them while she killed In Khorne's name.
Best believe that evey Astartes chapter, Sisters of Battle, Guardsmen, Inquisitor and etc are gonna wanna sign on for the chance to get it back in Blood. Since If Atalanta is back to normal again then that means she can't respond and isn't roided out by Khorne anymore. And with how many bridges Rose has already burned I doubt Centurion, Squire, Magister or any of the S.O's are gonna help him and Atalanta either. Since it's quite literally a matter of " We aren't fucking with her, after how many bodies she caught" type energy.
As such I feel like this is a fun little thing that I think should get tackles more, because Rose can't really do shit even if he gets Atalanta back who will now have a massive C'tan sized target on her back from both ends.